Good morning, everyone. Welcome to the fifth meeting of the Net Zero Energy and Transport Committee. Today's only business is an evidence session from the president-designate of COP26, the right honourable Alok Sharma MP, who is joined today by three colleagues, Peter Hill, COP26 chief executive officer, Wasimair, COP26 chief operating officer and Lee McDonough, director general, Net Zero and international at the department for business, energy and industrial strategy. Mr Sharma, we know that you have an extremely busy schedule with your preparations for the COP26 summit, so we are extremely grateful for you and your colleagues joining us this morning. I understand that you would like to begin by making an opening statement, so I will hand over to you at this stage. Thank you. Great. Well, thank you very much indeed, chair. It's a pleasure to be here. Obviously, I have Peter Hill and Wasimair from the COP unit who will help me answer any questions you may have related to COP and international engagement and logistics and all those issues. Of course, Lee McDonough from Bays, who leads on net zero strategy, and I'm sure we'll be happy to address any questions you have on domestic or Bays-related policy. From my perspective, as the COP president-designate and as part of the COP unit, we have been doing a significant amount of international engagement in terms of preparing for COP26, which is now, of course, less than two months away. I think that it would be useful briefly to set out what it is that we are hoping to get out of COP in terms of targets that the world can aim for. Your committee members will be aware that, back in 2015 in Paris, world leaders agreed that they would work to ensure that average global temperature rises were limited to well below two degrees, aiming for 1.5. I think that the overarching message that we would like to get out of COP is that we have kept 1.5 within reach. Your committee members will also have seen the IPCC report that came out in August, which painted a pretty stark picture of where we are. I'm basically saying that the door, the window, is basically closing on 1.5, but there is still room if countries act now. As part of the message that I've been taking to every country, there are four things that we are asking them to do. One is on mitigation, so ambitious 2030 emission reduction targets and net zero commitments for the middle of century. We have made some progress there. All the G7 have committed to net zero by 2050, but also 2030 targets that align with net zero. When we took on the COP26 presidency, less than 30 per cent of the global economy was covered by a net zero target, where now it's 70 per cent. However, we still need other countries, particularly some of the G20 nations, which have not yet come forward with ambitious 2030 emission reduction targets, to come forward. The second thing that we're asking countries to do is to set out plans for adapting to the climate change that is already happening. As we saw from the IPCC report, even if global warming stopped tomorrow and climate change stopped tomorrow, the effects of what has happened already will continue to reverberate for a long period of time, so countries need to plan for that. Thirdly, we are asking developed countries to deliver on their promise of $100 billion a year funds mobilisation to support developing countries. That was supposed to happen every year from 2020 to 2025. We are not there yet. We have had some new money that has been announced, significant new money that has been announced by a number of countries. Clearly, we need to do more so that we continue to press the donor countries on that, and we are going to be setting out a delivery plan ahead of COP on that. The final piece of the puzzle from our perspective is closing off the remaining outstanding items on the Paris rulebook. There are detailed rules still after six years that have not been resolved in a number of areas, and we hope that that is something that we can reach agreement on. I very much want to see this as an all-of-UK COP, something that we can all collectively be very proud of. Of course, we will be welcoming the world to Glasgow. I think that this is an opportunity to showcase what the United Kingdom also has to offer. We have been working very hard on the logistics of making sure that this is a safe and secure event, and I am sure that we will address that through the questions of the committee. Thank you very much for that, chair. Thank you very much, Mr Shamber, for your opening remarks, which provided an excellent overview for this session. We will now move two questions from the committee. My first question is something that you alluded to in your opening remarks about what we might expect to see from COP26, in terms of what will be the key indicators of success that we will be looking for coming from the conference. Is it right to say that there is this time around? Can you hear me now, Mr Sharma? Bear with us a second and we will try to fix this. We will suspend the meeting for a short time. We are good? Yes. Okay. Mr Sharma, can you hear me now? I can indeed, chair. Yes, indeed. Excellent. Apologies for that technical issue. My first question related to the indicators of success that we may look out for coming from the conference. You alluded to some of those in your opening remarks, but I wonder if you could talk a bit more about what those key indicators of success will be, because my understanding is that there is quite a wide range of criteria and objectives that all parties are looking to achieve, including the international climate financial support that you mentioned, nationally determined contributions from each of the states, and the sharing of low-carbon technology and policy platforms with developing nations. I wonder if you could touch on some of those issues, please. Yes, of course. In terms of the overall indication of success, as I said, I think that what we will want coming out of this is for independent parties to be able to say that we have kept 1.5 within reach. You mentioned, chair, the NDCs. Obviously, we have now had, I think, well over 100 countries that have come forward with NDCs, but obviously there are almost 200 parties that have signed up to the Paris agreement. Some of the biggest economies in the world, some of the biggest G20 nations have not yet come forward with revised NDCs. I was at the July ministerial meeting of the climate and energy ministers in Naples, and as part of the communique, there was an agreement that every G20 nation would step forward with enhanced NDCs before COP26. We are waiting to see what comes out of that. Obviously, at the UN General Assembly, next week, there is an opportunity for countries to make further announcements, but it is also going to be quite important that we get further net zero commitments. I think that we have made significant progress going from 30 per cent of global GDP to 70 per cent of global GDP covered by a net zero commitment, but I think that that is going to be very important. Finance is going to be absolutely critical. I think that this 100 billion figure has become a matter of trust for developing countries. That is why, for me, it is absolutely vital that we are able to show a delivery path to 100 billion a year over the five-year period from 2020 to 2025. As I said in my opening remarks, we are working on a delivery plan being put together with our colleagues in the German and Canadian Government, where we hope that it may be possible to demonstrate the funding that is coming from sovereigns, the funding that is being mobilised from the private sector as a result of public funding going in, the funding coming from multilateral development banks and any other finance mobilisation that is taking place. What we did see at the G7 leaders, we did see additional new money coming from Germany, we saw new money coming from Canada and from Japan, and the UK, of course, also committed back in 2019 that we would double our international climate finance commitment. Clearly, we need all of the G7 to come forward with more money. Indeed, in that communique that I referred to, there was a clear agreement that there would be further funding coming forward in terms of climate finance. The final piece is bringing that back to the real economy as well. We are very much driving the push on the end of unabated coal use, the end of international financing for coal. We have made some progress. All the G7 have now agreed that there is no more international coal financing from this year. South Korea has done the same. We need all the countries that are financing coal to do the same. In terms of zero emission vehicles as well, we want to see countries come forward with commitments to have only new sale of vehicles. The UK, of course, is committed that from 2030 we will only have the sale of electric vehicles in the UK. The other big issue has been on afforestation. We want to see more policies coming forward in tackling deforestation that is going on around the world and, of course, sustainable agriculture. In each of those three policy areas, we have set up mechanisms whereby Governments around the world are able to come together and have that discussion. We have a zero emissions vehicles transition council, an energy transition council and agriculture. In our precedency year, which will not start until November, which will then have a year to run, we will take forward a lot of those issues as well. It is an opportunity to drive forward a lot of the real economy changes that also need to happen to deliver on the commitments that Governments are making. Thank you very much for that. You touched on the importance of the financial support and some of my colleagues will follow up on that shortly. You also mentioned that, obviously, we then have a year following COP immediately to look at what the outcomes are. I guess that is my next question looking at the implementation stage, what happens after COP26 and the agreements reached COP26. I guess that there are two elements to my question. First of all, how will the UK Government take forward the outcomes agreed at COP26 in terms of new strategy or legislation? Secondly, from a global perspective, do you have an expectation that the UK net zero strategy and any new climate targets agreed at a UK level and a Scottish Government level will set the template for other nations to follow? I have had a lot of international engagement over the past year. I can say to you that people around the world see the UK as a leader on green growth. If you look at energy, we have now got the biggest offshore wind sector in the world. We have taken the use of coal in the UK energy mix from 40 per cent in 2012 to less than 2 per cent now. By the end of 2024, there will be no more coal in our electricity mix. We are the first country to have a major economy to legislate for net zero. We have a really ambitious NDC ourselves. We have a very ambitious six-carbon budget target as well. We are setting the template. During 2020, when I was combining this role with my role as base secretary of state, I spent a lot of time trying to persuade countries to come forward with more ambitious NDCs. I was always politely told that they were quite looking forward to seeing what the UK was going to do. We did set out a very ambitious NDC in December. That has allowed us to speak with some authority on that particular issue. During our presidency year, we are planning on that at the moment. I could be new some of the elements that we want to drive forward. I want to say to you that we will be an active presidency. Obviously, COP 27 will be held in an African nation. There is always a lot of liaison that takes place between the presidency that is handing over to the new one. We will of course work very closely with whoever in Africa is awarded the COP 27. Good morning, Mr Sharma, and best wishes for a successful COP 26. Following up your comments about leadership and ambition, Scotland has a great deal of ambition, and indeed the UK will not be able to meet its targets unless Scotland meets ours and vice versa. In looking at COP 26, I am interested in your advice as to how we can secure whole of UK input into COP 26. What do you think we have got best to offer in terms of demonstration on offshore renewables? On just transition, I was struck by what you said about G20 countries. We know from Professor Richard Sgear that the IPCC is interested in our approach on just transition, particularly in reference to coal. Perhaps that might be a helpful platform that may be useful at COP 26. It was a pleasure to work with you previously on those issues, so I am very pleased that we are having this conversation. I have been very clear on that right from the start. We want to see that as showcasing what the UK is doing. You will know, because you were part of the grouping, that we have a devolved administration's ministerial group that I chair, which brings together the ministers responsible for the issues from all the devolved administrations, together with ministers from the Welsh, Scottish and Northern Ireland offices. The last meeting that we had was yesterday. I have to say that the collaboration on the logistics and planning has been really good with the Scottish Government, with Glasgow City Council. It has worked really well. Peter Hill, who is the chief executive of COP 26, also chairs the delivery board, and he may want to add a little bit more about that close working. In terms of showcasing the UK, you will know that the venue is going to be divided into the green zone, which is effectively open to the public. We had significant levels of expressions of interest from businesses, NGOs, academia, etc., to display in the green zone. We did liaise with all the devolved administrations in terms of the submissions of interests that came in. We will be showcasing from a Scottish perspective quite a number of Scottish-led initiatives in the green zone. In terms of the blue zone, what we have said is that we are going to have a lot of focus on the region cities, the build environment day at COP. There is a theme day every day, and on that day there will be focus on the devolved administrations. However, as I made very clear yesterday in my conversations with the ministers, we set out for them more detail of what we plan to discuss on each of these days over that two-week period. I have asked them to come back to me and my officials on how they might want various devolved administrations to be involved. Thirdly, in terms of the UK pavilion itself, we are having a discussion about how we can showcase in the UK pavilion the work that is going on across the devolved nations. Can I maybe focus a bit on policy aspects? Clearly, in terms of delivery and your role over the coming year post the actual COP26, the issue of delivery is going to be very important globally. Therefore, states will have to work with substates in terms of that actual delivery. That is where the good co-operation between Scotland and the UK would be really important in showcasing what can be done and should be done because of that dependency in terms of targets that we talked about previously. Is that an opportunity for again Scotland to help in a global stage to show how substates can deliver on energy targets? I hope that we will see all of that. That is why I am keen that we get further feedback from all the devolved administrations on the plans that we showed them yesterday in terms of the detail of what is going to be discussed on each of the days. What we have set out so far publicly is the theme on each particular day, whether it is energy or transport or regions. I think that there will be an opportunity for the devolved administrations to showcase what they are doing. You raised a very important wider point about net zero strategy. The UK Government has been pretty clear that we will set out a net zero strategy before COP26. There is a lot of detail work that is going on. Obviously, there is a lot of liaison that takes place between Bays, colleagues and colleagues in the devolved administrations. Obviously, there is an interministerial group that has been set out, which I think is working well. With your permission, if I could invite Lee Macdonald to come in and say a little bit about that domestic working arrangement, which I think is so vitally important. As just referenced, with devolved administration counterparts, Bays has established an interministerial group that covers net zero energy and climate change. It meets bi-monthly and brings together ministers from the four administrations to discuss admission reduction efforts across the UK. That is at the ministerial level. We have really had constructive engagement, but that is backed up by a really significant and quite extensive official level set of engagements as well between Bays and the devolved administrations at senior official level. We have something called the net zero nations board. At working level, we have a whole load of working groups that support that. The net zero nations board meets bi-monthly. It is chaired by a senior-based official. I met four times last year to cover a whole range of issues deep dives across the majority of the policy areas that are in the strategy. I will ask the convener to move on. I believe that Mark Ruskell has a supplemental in this area. I want to ask you about the UK Government's engagement in the beyond oil and gas alliance, where the initiative is being led by the Danish Government. It seems to be building up quite ahead of steam. We have Germany, Iceland, Costa Rica, Belize, Portugal, Netherlands, Ireland and New Zealand that are all engaging in the work of the alliance. Can you ask what the conversations have been so far with the Danish Government about this and how you intend to engage in this conversation that will be launched at COP26 in Glasgow? Obviously, there is a range of conversations that are taking place. In terms of what our domestic policy is going to be on oil and gas, we have been pretty clear on that. The Government has already set out that there will be a climate compatibility checkpoint that will assess any future licences for oil and gas. I think that the intention is to set out more details on that at the end of this year. Perhaps Lee might, from a base perspective, want to elaborate on that. Obviously, we are having a whole range of conversations across a range of policy areas. I was in Copenhagen some months ago and had a meeting with ministers and the Prime Minister as well, discussing, as I said, a range of issues. I know that, Lee, if you wanted to comment, because ultimately this comes down to domestic policy, if you wanted to comment on this. Yes, thank you.  It was announced earlier this year and will be in place by the end of 2021. That will be used to assess the climate compatibility of future licensing rounds. Our current thinking is that it should basically look at industry progressing in the different commitments in the North Sea transition deal, how the UK compares to other oil and gas producers in terms of reducing emissions associated with production, and whether the UK continues to need domestic production to reduce our dependency on imports. We will be going out to seek views on the checkpoint shortly. That is the plan to be in place by the end of the year. I believe that Jackie Dunbar has a supplemental in relation to the UK Government and the Scottish Government working together on COP. Good morning, Mr Sharmer. I think that it was touched on briefly, but could you maybe go into a bit more detail about how you think the UK Government are liaison with the Scottish Government to achieve an ambitious global deal? Are there any areas that we are overlapping and how much co-operation is there? The COP is quite different from Paris. In Paris, it was very clear that there was effectively one agreement that we were trying to reach. Here, what we have is a number of strands. One is on mitigation, as the chair said, the NDCs and necessary commitments. We are asking for adaptation communications to come forward, we are asking for finance, and then, of course, closing off those elements of the Paris rulebook, which ultimately there are officials within the UK Government who are very involved in those negotiations with countries around the world. All of that will obviously come together in cover decisions coming out of COP and anything that comes out of the world leaders summit, which takes place in the first few days of COP. Collectively, what that will hopefully do is to be able to demonstrate that we have kept 1.5 within reach. I think that where we have colleagues are able to encourage policy changes elsewhere—NDCs, of course—that is welcomed. In a way, there are so many strands that we are trying to tie together here, and a lot of that will come down to the negotiations in the final two weeks. As I said, we have a negotiating team in the UK Government that has been beavering way on this for quite some time now, talking about counterparts internationally. Just to ask another quick question, what advice would you give to the Scottish Government and the Parliament on how they can play their part in a successful conference? What role do you think the First Minister can play in this? Let me take the First Minister's issue first. Prime Minister Johnson has said that he wants all the First Ministers to play an important part. There is work going on at official level looking on this. As I have said very clearly, we want this to be a whole-of-UK approach. I am sure that, shortly, you will hear more from the UK Government on this issue, but I said that this is something that the Prime Minister leads on. In terms of the involvement of others in Government from the devolved Administrations, there has always been the presence that, as part of the UK delegation, we have representation from ministers in the devolved Administrations. That will absolutely happen again. In fact, we are in detailed discussions right now, which each of the devolved Administrations is in terms of numbers of people who would join the UK delegation. The third strand of that is parliamentarians. Shortly, we will be communicating with the presiding officers in each of the DAs in terms of suggesting how members of those legislators are able to come to COP and get access on the days that they want to the blue zone. We also have a glow that, as all colleagues will be aware, is organising an event in the Scottish Parliament on 5 and 6 November, which is going to bring together international parliamentarians internationally as well. That is an opportunity for, frankly, all parliamentarians, whichever legislative they sit in, in the UK to also get involved as well. Thank you very much, Jackie. Let me bring in Liam Kerr. Thank you, convener. Good morning. Just taking you back, Mr Sharma, if I may, you mentioned the nationally determined contributions earlier and the need to mobilise international financial support to assist developing countries to meet those NDCs following COP26. Regardless of whether the amount ultimately agreed is 100 billion dollars or otherwise, how will this financial support be administered, allocated and shared with those countries that are most in need of support to meet their targets? Obviously, as I said, we are putting together a delivery plan where we will put in place or demonstrate how much money is coming from individual governments, how much money is being mobilised from the private sector as a result of the public money that has gone in from individual governments, how much is coming from the multilateral development banks and any other finance that is being mobilised. If I take the UK Government, we have a significant international climate finance commitment and we will allocate finance to individual projects around the world. That will be the approach that other sovereign nations take as well as the multilateral development banks have targets for how much they want to put in terms of funding into climate projects. Those decisions will be made in either those governments or in those multilateral development banks. However, what we want to see and be able to demonstrate is that there is a quantum of money that equates to 100 billion a year from 2020 to 2025, by which, credibly, developing nations can look at and say, yes, we can see where that financing is going to come from. It is a very good mechanism, so we are right now in discussions with individual governments and multilateral development banks. I have been having lots of those discussions to get their forward figures as well, so we can see what is likely to come forward. As I said, I think that this is a key element of this. There are two key issues that we want to make sure. One is that the finance is delivered and secondly that the mitigation targets come forward as well. I think that some developing countries will say that without finance it is going to be pretty challenging. Thank you very much. The second question, again sticking with the financing, if I may. If we look at the UK Government's financing to reach climate change targets, the climate change committee has estimated that an extra £50 billion a year of capital expenditure is going to be needed from 2030. Does the UK Government take any view on whether that estimate is reasonable and in any event? Can you help us to understand how that will be financed? Yes. I think that your reference is effectively to the cost of getting net zero domestically, is that right? Yes, the report from the Climate Change Committee, yes. I think that the first thing I would say to you, and this is a more general point, global point, is that the cost of inaction on climate change is most definitely greater than the cost of action. You will be familiar with the Stern review that came out a few years ago, authored by Lord Stern, who sits in the House of Lords and is an eminent economist, who said that the global cost to the global economy of unabated climate change is anywhere between 5% and 20% of global GDP. In terms of what we have said, and I will ask Lee to come in, because I guess that this comes down to domestic issues as well, I think that what we have said is around under 2%. Obviously, there is a net zero review that is undergoing, and the Treasury will be setting out more details of that before COP26. Interestingly, what the CCC said is that, back in 2015, they had a report that said that the cost of the move to net zero was around 2% of GDP. In their latest report, which came out last year, I think that it was anywhere between 1% to 2%, and the reason that they said that the cost was falling was because at the pace at which renewables technology and other technology was developing and the price of that was coming down significantly. If you look at the price of offshore wind around the world, including, of course, in the UK, if you look at solar, there have been significant drops. I think that in terms of solar, 80% drop in prices over a 10-year period. I think that when we talk about cost, we also have to look at what the upside is. On a UK-wide basis, through successive Governments, we have, on a 30-year period, managed to grow the UK economy by almost 80% in terms of GDP, but we have also cut emissions by over 40%. We are seeing around the world, as a country that has demonstrated that green growth is possible. We also have to take into account all the other benefits of having a cleaner environment in terms of the impact on people's health and wellbeing. I don't know, Lee, whether you may be a little bit closer on this from a base perspective, but I don't know whether you want to comment at all on overall costs of net zero. Thank you, CPD. You basically said what you said is correct in terms of the headline figures. I will just say that some of our most important work that we are taking at the moment is on the cost of transition. You are right that low-carbon investment needs to scale up to around £50 billion each year to deliver net zero and support the UK's economic recovery. The investment generates substantial fuel savings, as cleaner and more efficient technologies replace their fossil fuel predecessors. In time, those savings cancel out. The investment cost is highly and a new piece of insight from our work means that our central estimate for costs is now below 1 per cent of GDP through the next 30 years. If I could just add in terms of the domestic focus, we are looking at a combination of public and private investments and the relationship between the two components varies depending on the stage at which sectors are at. A large part of our strategy will be published ahead of COP. You will have seen in some of the strategies that have been published recently that the hydrogen strategy or the industrial decarbonisation strategy focus on work that the Government needs to step in to provide transition support to help industry develop and invest in the technology that we need to see in order to meet our targets. Thank you for such a full answer, which I find fascinating, if I'm honest. The final thing, convener, if I may, is just one more question to pick up on something that the director general mentioned earlier. The UK is the first G7 country to agree the North Sea transition deal, which is worth between £16 billion and £18 billion. That has leveraged private investment, which will support the oil and gas industry transition to a clean green energy and support jobs. Within that deal, the sector has committed to cutting emissions by about 50 per cent by 2030. The Government sector and the unions are going to work to deliver the skills, innovation and infrastructure to decarbonise North Sea production. Will COP26 have any impact on the transition deal or does it remain as is? Lee, do you want to take this from a domestic perspective? I can talk a little bit more internationally. I think that the transition deal, as you mentioned, is a global exemplar. That deal has been struck domestically in terms of the Government and relative industries. It includes supporting up to 40,000 high-quality direct and indirect supply chain jobs and generating up to £16 billion of investments, as you have quite rightly flagged up to 2030. The really good thing about the deal is that the commitments in the deal achieve 60 megatons reduction in UK greenhouse gas emissions. That includes the commitment that you referred to from industry to reduce down emissions to 50 per cent by 2030. The COP link to it, so that deal exists. The COP link can be to showcase what we have done here and be an exemplar to other countries and show them how we can do that, just transition, making sure that we are protecting supply chains and jobs and transitioning to support lecoven industry and technologies. I think that the issue of just transition is something that I think every country is facing. When I have spoken to other Governments, this is something that they all get. For instance, when I was in Spain, there was a discussion about how the Government working with the trade unions was looking at the issues on just transition, in the same way that the UK has a green jobs task force where trade unions are also represented. I think that this is a key element of this. If we are not just from a UK perspective, but internationally, if we are going to deliver green growth, it has to be in a manner that also means that those who are in sectors where jobs are reducing are able to get the skills and the support to move into new jobs. I think that that is a critical issue that every country faces right now. Good morning, Mr Sharma. I wholeheartedly agree with you that COP26 is an opportunity to showcase what the UK has to offer. With the IPCC report warning that the door is closing on 1.5, would rejecting the new cambo oilfield ahead of COP26 be a strong example of the climate leadership that the global community is looking for? Perhaps a second point that your officials could pick up? Will new oil and gas developments be reassessed in light of the recent IPCC and IEA reports? If so, will that include an economic analysis, including carbon dioxide costs of the cambo field and others, as proposed by Professor James Skea from the Just Transition Commission? Thank you for that question. In terms of cambo itself, this is obviously now a domestic policy issue that sits with base. I will leave it to Lee to give further details on that. I would just point out that this was, of course, a licence for this field that was originally awarded back in 2001. What we have been very clear about is in terms of future licences, and for them to be compatible with our climate law, the fact that we are going to net zero by 2050, there has obviously been a public inquiry on cambo. I think that maybe at this point rather than speak for base, I pass to Lee to talk in any more detail if she wants on cambo. Thank you. I lost connection for a second, so I guess you were just asking about where we were in the licensing process. As CPD just said, the licence for the cambo oil field was granted in 2001. The developer has now requested to move to the production phase, which requires a consent in order for that to happen. Therefore, the next stage of the process was just a thorough assessment of the potential environmental impacts of public consultation, and scrutiny by the Oil and Gas Authority is under way. No decision has been made yet on that process, so I cannot say any more about it other than to reiterate the point that CPD made. Development for fields that have existing licences are subject to a rigorous process, so an environmental impact assessment, as I said, is a public consultation, as well as that scrutiny from the Oil and Gas Authority before consent is provided, and all future licences will only be granted on the basis that they are compatible with the climate compatibility checkpoints that we referenced earlier, which will come into effect at the end of this year. We will seek views on the nature of that checkpoints process shortly. Thank you for that response. I apologise if there was a slight technical issue. That brings me perhaps to my second question. I sympathise with Mr Sharma, because you have had the role of speaking to people around the world. That has involved a lot of travel, which you have been criticised for, but we perhaps can sympathise with why the in-person meetings can be more efficient. Has all that travel and face-to-face negotiation been worth it? What have been the key achievements from that? If I can, because I think that we all have high hopes for COP26, but can I ask what are your fears about COP26? On that note, is there anything about the conference that is keeping you awake at night? Yes, what is keeping me awake at night? Quite a lot, in terms of where we are less than two months ago. I do not think that it is an exaggeration to say that COP26 is our last best chance of getting this right. This is a decisive decade, and all colleagues asking questions on this committee have made reference to the IPCC report. That is why we need to get this right at COP26. In terms of my travel, I think that face-to-face discussions have been incredibly vital in building the personal relationships. It has meant that we are able to have more fruitful discussions. If I take some examples, when I have been to South Korea on two occasions, we have had a very good announcement coming out of South Korea in terms of ending international co-financing. That is an issue that, from a UK perspective, we have, of course, been raising with South Korea. I am delighted that that commitment has come forward. I was in Japan, ahead of Prime Minister Suga, announcing Japan's NDC. I was very clear, both in meetings with him and ministers and in the public, about the fact that we wanted to see Japan get to 50 per cent NDC. When the announcement came, I think that it had a range of 46, but with an ambition for 50 per cent. I think that I could go on with a list of things. Just to be very clear, this is not just me. This is a whole team that has been working over a long period of time on these issues. The fact that we have gone from less than 30 per cent of the global economy with a net zero target to 70 per cent, I do think that that is something that the UK can say that we have helped to come forward with. In terms of COP itself—we may come into that discussion, but I have been very clear right from the start that this has to be a physical event. That is what I have heard from countries around the world as well, particularly for developing nations and climate vulnerable nations. They want to sit at the same table with the big developed nations, with the big emitters and look them in the eye. Ultimately, this is a negotiation amongst almost 200 countries, and that is why it needs to happen in physical form. I reiterate what I said at the start of the session, which is that I want to see the biggest emitters coming forward with those emission reduction targets that are going to take us to a point where we can say that we have kept 1.5 a life. I do want to see the money coming to the table. I do want to see the donor nations pony up the cash. Ultimately, there are a number of outstanding but pretty complex issues from the Paris rule book that we also need to get resolved. This is a little bit like playing an incredibly complicated game of chess. I said to someone on the media that it is a multi-dimensional chess, and it has pointed out that that does not exist, but I can tell you that it feels a little bit like that. Mark Ruskell, to be followed by Collette Stevenson. I can just come back to the points made about how UK policy on oil and gas is perhaps evolving, particularly in terms of how you stay aligned with the Paris agreement. I am wondering if that policy of maximum economic recovery actually puts the oil and gas companies in quite a difficult position. If I was on the board of shell, and I am not on the board of shell by the way, but if I was, I would be faced with, on one hand, a ruling from the Dutch court that says that, as a company, we have to reduce our emissions by 45 per cent, not just in terms of production, but in terms of sale of all fossil fuels. On the other hand, if I have a licence under maximum economic recovery, I have a legal obligation under UK law to extract every single last drop from those reserves that are licensed. Can you see the difficulty here in terms of making that transition under the current policy of maximum economic recovery? If you do see that, how do you see that policy changing over time? I think that the first thing that I would say is that, when I was still at base, we put out an energy white paper, which showed how we were going to effectively move forward to 2015 in terms of our energy mix. I think that that is still assumed, that there would be, under various scenarios, you could still see some oil and gas. In fact, I think that the IEA put out a report recently, in fact I asked if they would put it out and work on it, where they showed what needed to happen in terms of the world moving to net zero by 2050. Even as part of that, some element of oil and gas was significantly reduced, of course, but some element of oil and gas in the global energy mix. I do not know if you want to talk specifically from a domestic perspective in terms of the particular tension that Mr Russell referred to. Thank you. You friend it perfectly. We are doing a huge amount, as you know, to drive down demand for fossil fuels, but there is going to be a continued on-going demand for oil and gas over the coming years. That has been recognised, as the CPD said, by the International Climate Change Committee, and that is the case. The UK continental shelf for mature oil and gas basin and production is declining. We expect the rate of decline to be broadly in line with our domestic demand as we transition to penal sources of energy. Do you reference previously licensed fields such as Cambo? They are already accounted for in terms of projected production and estimated emissions, and therefore we are confident that they can be developed if they get through the process that we talked about earlier about the degree of scrutiny to be given a consent. We are confident that they could still go ahead as we seek to achieve our commitments to net zero in 2050. That suggests that there is some need for oil and gas going forward, but that is not the same thing as maximum economic recovery. That is not the same as 20 billion barrels of oil and gas in the North Sea. That might be somewhere south of six billion barrels. I think that we are getting into some of the detailed domestic policy here, but if I may just make a more general point on this, if you look at the projections that have been put out there for 2050, we are looking 30 years ahead. We have seen globally what happens when, for instance, renewable energy, clean energy is mobilised at pace and scale, and what happens in terms of price. There are various scenarios that people have in terms of what the global energy mix might look like. I am not here speaking on behalf of the oil and gas majors that they speak for themselves, but if you look at what some of those companies have been saying about moving to being energy providers rather than oil and gas, I think that there are companies as to how the world is changing. I have Peter Hill, who is the commandant. Peter, it was then that you wanted to add from an international perspective.  I thought that you might want to come in. If not, it is fine. Yes. It was related to an earlier point, but it is also relevant to the wider oil and gas question. Just to recall that last year, the Government announced that it would be phasing out support for international oil and gas export credits, et cetera. Obviously, that is more effective if a number of countries are taking that path. We are working with a number of countries who are moving in that direction. There have been some announcements recently from the United States. It was related to the broader issue, but just to say that is an area of work that we are prioritising from COP in order to see who is prepared to bring forward their commitments, both in time and substance, recognising that we need to support countries in the transition but also recognising that the more countries who can reorientate their financial and guarantee support from the oil and gas sector to the renewables sector, the better. As I said, it was relevant to an earlier point, but I think that it is still relevant to the broad discussion. I was told that R is the thing to put in the chat if you want to come in. I see that Lee has also put R in the chat, so I just mentioned it. I just wanted to flag, which I should have said earlier. The oil and gas authority strategy, which has recently been updated, plays an obligation on industry to support net zero. The strategy makes it clear that maximising economic recovery includes a net zero consideration as part of that obligation. Let me bring in Collette Stevenson with a brief reminder that we need to finish by 11.30. I will focus on financing the net zero and based on the consumer. How do you feel about it? Should the capital costs of decarbonisation be paid for by the consumer through electricity bills or gas bills or more widely through taxation, or other wider means? Obviously, at the heart of this is our consumer, so I came to see how that is going to look on forward. If I may, I think that I am going to end up intruding on HMT and based policy here if I start commenting on that. Lee, I do not know if you feel able to say anything about that. Obviously, the HMT's net zero review is going to be coming out before COP when people will be able to have a look at that. Was there any other point that you wanted to make on the issue of where the costs fall? As you said, the Treasury's strategy will set out and broad-term the analysis around the whole issue. I will refer back to the points that I made earlier. There is a combination of public and private investments and a balance between the Government's support and the Exchequer support, depending on the stage that individual sectors are at. Ultimately, we all share responsibility, including through consumer bills and industry bills, to support our transition. I do not think that it is a one-size-fits-all position. It is a very nuanced issue. The Treasury's strategy will set out our plans on the front. There has also been touched upon the risk of carbon leakage and how it can be mitigated. Can there be an agreement on carbon price and be reached at COP26? The point that you have raised is incredibly important and pertinent. What we are trying to resolve in Glasgow, on the road to and at Glasgow, is article 6, which is the Voluntary Carbon Markets. That is separate to perhaps the wider discussion that is going on in terms of carbon border adjustment mechanisms and wider issues on carbon leakage. I have been very clear not to conflate the two, but there is no doubt that, when it comes to sea bams, there is a very live discussion that is taking place. You will have seen the EU earlier this year set out their initial thoughts on that. From a COP26 perspective, this is not a mandated item. What we are trying to resolve is on article 6. Peter Hill has come back into view. I do not know whether Peter Hill wanted to add, because you have been having a lot of those discussions as well with the team. I support that completely. The issue of domestic and international carbon pricing is very lively and the relation of that to trade issues. As you say, it is not part of the formal COP agenda, but it is not yet ready for that sort of international agreement. I am absolutely sure that, whether through the G7, G20 or other fora, that discussion is only going to continue and gather pace in the months and years ahead. Of course, the strongest way of addressing those concerns is by the mitigation action that everybody takes. That is one of the reasons why it is so important in the next few weeks that all countries, G20 and others, come up with those plans and commitments, so that those issues are managed so that we can have them in a collaborative and co-operative way. Thank you very much, Collette. We are reaching the end of this session. That completes our questions and concludes the evidence session. Let me thank Mr Sharma and his colleagues once again for their unique insights into COP26. On behalf of the whole committee, we wish you the very best of luck for a successful outcome at the conference in Glasgow. Thank you very much and have a great day. That concludes the public evidence session.


In this study, eight compositions of BATIO3, BT, were created using substitutions of various elements into the material. These compositions were tested for their energy storage density and efficiency, as well as their dielectric characteristics. The best composition, with a doping level of 0.12, demonstrated a high energy storage density of 1.75J-CM3 and a high energy storage efficiency of 75%. Additionally, the curie temperature of the material was found to be around minus 20°C, making it suitable for use at room temperature. This article was authored by Joshua Nson and UNJelly.


Good morning to all of you and welcome to the fifth day of this workshop. If you look at the schedule for the morning sessions, we are mostly going to deal with complex friction and basically as we have you know considered during the coordinator workshop, we are going to look into belt friction as well as square threaded screws that is screw jacks more or less. So, just to start off with as you have seen that friction you know we are approximating the solution on the basis of Coulomb friction or dry friction we also sometime call that point friction. Again that is a very rough assumption and as we all know that friction will depend on the tribology between the contacting surfaces. But more or less what we have studied that if you for the time being just consider the point friction then the analysis could be very simple. Only thing that we have to careful is with the direction of the friction force, how it is going to act that is the first one. Secondly as we have all seen that when we try to look at problem involving impending motion that means most of the problem that we look at without slippage problem. That means what is the for example if we look at a problem that I am trying to really push a body up on an incline then my question would be let us say what is the load required to just push the block up on the incline without slippage. So, I am really therefore trying to you know enforce the condition of impending motion. And what it does basically it does you know and one thing that you have noticed that it makes the number of unknowns equals to number of you know conditions that are required to solve the problem. So, remember the friction you know law therefore that actually tells me or allows me to solve the problem in a statically determinate way. So, therefore, when we have multi body interaction if we have looked at it carefully we have said that in a multi body interaction problem let us say we have you know two contact surfaces may participate. In that case what was the main you know principle that we have used first we try to identify the number of unknowns. So, we have identified the number of unknown forces right then we have limited number of equilibrium equations right. So, we have always seen that number of unknowns exceed the number of equilibrium equations and therefore the balance unknown ok. So, that is the total number of unknowns minus the number of equilibrium equation that is my balance unknown and what we do is basically if the problem is self consistent we are going to say that I should have that many contact surfaces where I would induce the friction loss. So, it is as simple as that in word however remember we are always enforcing a problem which is statically determinate in nature and you have seen this from the very beginning that no matter what topic I choose my problem is always statically determinate otherwise what happens in the process that to if the number of forces exceed the number of equations then we need to invoke the you know deflection that means kinematics as well deformation of the body as well to solve for the additional unknown forces. With that what I will now try to look at some of the complex friction now why do I call it complex friction. Remember as you see in case of a belt friction what is happening I have illustrated few different examples here. For example, here you have a rope right that is passing over a bollard. What is the objective the person can actually apply a very small amount of force to hold a very large load. You can see this very often if you go to jet ease for anchoring of boards for anchoring of ships and so on so forth. You can see that by applying a small force I can hold a large amount of load. Similarly now what is happening that there is a large area of contact coming into play however remember friction force is distributed between the rope and the surface. However we are going to introduce the fact that we can still say that each and every point on the contacting surface should have simple friction law that means Coulomb friction and we are going to derive the relationship between the tension on the both sides based on that. So ultimately if there is no friction for example between the pulley and the rope then we say the tension in the both sides are same which is perfectly fine. But when the friction exists then we should understand that that force that is the tension in one side of the belt will differ on the other side. So again this problem will help us to you know study applications that involve raising or lowering the loads. One thing that instantly come to our mind is as follows. I would always require small force to hold a load. Suppose I put a 20 kg block here I would probably need 5 kg to just hold the both block. Two conditions are coming into play. In one case in the first case the block is trying to go down that is impending motion is downward. So we are trying to invoke the impending motion condition when it is simply trying to go down and we are trying to find out what is the load required to hold this body right here. Similarly in the second case if I consider the impending motion upward right then what will happen I have to apply a large amount of load and that is all possible because remember the friction direction is always being changed here it is being reversed as you look at the problem involving loading you know holding the load or the problem involving just raising the load. So friction will change the direction and tension side will always be on end side that we will try to oppose the friction force the larger tension side ok. So another application as you see here that is you know we see in the transmission of torque problem right. So you have somewhere a motor that motor may be connected to some machine tool. So we have again pulley or drum and belt problem ok. Remember this problem however we will be tackling based on the fact that both are rotating at a constant speed. If both rotates at a constant speed then we will try to understand that when the belt is trying to slip over the drum what relationship exist between the tensions of these two. We should first try to understand also that where the slip would happen first whether it is going to be in the motor or whether it is going to be on the machine tool that is connected right that is being driven by the motor. The other example will be the band break problem. So you can see a disc and you have the you know band that is on top of the disc. Now you need some special arrangement here there may be a connected to a lever arm where we are going to apply a force. So once you apply the force this band is actually going to tighten on the disc and it will you know reduce the speed of this disc. So again our idea would be that can I find the force required such that a constant velocity is maintained here ok. So depending on the amount of force you can actually control the speed of the disc that is rotating. Remember here band is fixed on top of the disc or in other words there is a constant slippage between the disc and the belt or the band ok. Therefore this will actually involve kinetic coefficient of friction than that of static coefficient friction. So whenever we see that we have relative motion exist between the two contacting surfaces then we are going to say that we have to induce kinetic coefficient of friction. So let us try to just look at how do I derive the theory involving the belt friction problem. So what is the question here? The question is relate T1 and T2 as you see the T1 and T2 are the two tensions on the both sides relate T1 and T2 when belt is about to slide to the right. That means I am invoking the impending motion condition towards the right. So if the belt is just about to slide over this drum or let us say disc towards the right then which should be the direction of the friction. The friction will oppose the motion of the belt therefore friction will be on the opposite direction and we can clearly see therefore that T2 tension on this side has to be greater than tension on this side. Now remember as I said that there is a contact angle beta that plays an enormous role. So therefore we can easily get a feeling that whatever formula I derived T2 by T2 T1 relationship that will be completely controlled by this angle beta as well as the coefficient of friction between the belt and the drum. So now how do I get into the theoretical part? So again as I said it is a complex friction because friction is actually applied throughout. Now what we are going to enforce I am going to simply take a very small segment of the belt and I am going to apply the concept of point friction or simple friction there and I would assume that is everywhere and finally I have to get an integrated effect from P2 to P1. So that is the basic concept. Therefore let us just detach a segment PP prime. Suppose I detach a segment PP prime of the belt and I try to understand in this differential element that I have chosen PP prime what are the forces that have been induced. Since as I said that T2 has to be greater than T1 so I can see here that here I have T plus delta T okay and here you have only T and from the geometry we also understand that this angle is delta theta therefore this is delta theta over 2 delta theta over 2. Now here is the important part. The important point here is that I should have a normal force delta N that is given by the drum to the belt. I should have a friction force delta F. Now when the impending motion prevails then we say that delta F equals to mu s delta N that is our friction law. Now therefore you can see clearly that I have two unknowns in this problem one is the delta T and delta N right. So T and N these will be more or less my unknowns. So therefore now I will treat this body as a particle and I will try to understand that what is sum of force along x direction 0 and sum of force along y direction 0. So if we do sum of force along x direction 0 we see that T plus delta T cosine delta theta by 2 negative T minus cosine delta theta by 2 negative mu s delta N 0 that is one equilibrium equation and second equilibrium equation can always be written like this. Now we have to find out now I am only interested in finding out what relationship exists between T mu and beta let us say. So my objective here would be to somehow eliminate delta N. Therefore what I will do I will simply take this equation remember in this equation this term and this term gets cancelled. So delta N is delta T sin delta theta by 2 which I will simply substitute back here and therefore I am going to get this equation now this equation remember I have also divide everything by delta A delta theta because delta theta cannot be 0. So now what happens as you see now the equation has been revised I have one equation to play with and that equation becomes this ok. Now in the limit as delta theta goes to 0 what happens remember these terms will become 1 delta theta goes to 0 10 to 0. So this is 0 that is one what else happen when really delta theta tends to 0 we can also say the delta theta this one delta T right that is also tends to 0 ok. So therefore what I eventually get I eventually get a very simple equation which looks like dT by d theta equals to negative mu st that is equals to 0 ok. Now remember that we have to separate you know we have to use the separation of variables so we have dT by T must be equals to mu s d theta. So once I use separation of variables dT by T equals to mu s d theta and I will integrate both sides. So one side will go from T1 to T2 other side I will have 0 to beta. So theta should go from 0 to beta and T should grow from T1 to T2. So these are the two integration limit that I am going to use after separation of variables ok. So and that will lead to this because dT by T that is simply log of T right. So therefore we have log T2 by T1 equals to mu s beta because 0 to theta that integral will become beta. So ultimately what is the relationship T2 by T1 equals to e to the power mu s beta. So therefore what we have obtained that during the impending slip when the belt is just about to slide over the drum I have this relationship T2 by T1 equals to e to the power mu s beta. Remember there is no unique relationship that exists between you know we cannot find both T2 and T1 from just one equation. So what it tells me that I have a ratio that ratio is controlled by e to the power mu s beta where mu s is the static coefficient of friction and beta is the contact angle that should be measured in radian. So therefore to avoid the impending slip what formula shall I use T2 by T1 should be less than e to the power mu s beta. If there is no slip between the before the impending slip I should always use T2 by T1 less than e to the power mu s beta and if there is an actual slip that means there is a relative motion between the belt and the drum I should use T2 by T1 equals to e to the power mu k beta. So if there is a relative motion that exists then I should use e to the power mu k beta. So therefore again if we have to summarize we can summarize like this that when the belt is about to slide towards the right during that impending motion T2 by T1 equals to e to the power mu s beta. So it is completely controlled by the coefficient of static friction and the contact angle which is measured in radian we should first understand that T2 has to be greater than T1 if the belt is about to slide on this direction because all the friction forces will try to oppose that motion okay and remember that if there is no slip then T2 by T1 has to be less than e to the power mu s beta. If there is an actual slip that means there is a relative slip between the belt and the drum then T2 by T1 should be equals to e to the power mu k beta. Therefore I can actually you know take this problem to solve a large class of you know application we can consider using this concept. What are those problems? As I said the formula can be applied for impending slip condition for problems involving those are the applications I have shown in the beginning that flat belt passing over a fixed cylindrical drum okay. So that means your drum is fixed and belt is passing over that drum let us say you are trying to lower a object you know or you are trying to raise a object or you are trying to lower an object. So in those kind of problems it is going to come into play. Similarly ropes, belts you know around a poster, capstan or pulis we have gone through that also and belt drives. So this is going to be very important remember belt drives problem we have both the drum and the belt they rotate together at a constant velocity. So the question will be when there will be a slip between the drum and the belt. So now when it involves the motion problem that means when it is rotating at a very fast speed you can take one thing you could ask me that okay is there a centrifugal force. So did I consider that in that equation? So therefore now you can see the only thing is that we are always trying to understand here the main assumption is belt is always in contact with the drum. It should not try to you know just separate away from the drum. So in other words if the speed is really large we may have to include the rho omega square r effect in this formula. However as long as the mass of this belt remains small we can actually ignore that term as well. So remember in engineering mechanics problem we are always trying to approximate the actual problem and we are trying to get an answer which is as close as that of the actual solution. So we can always have this plus minus 10 percent error as we say okay in as a thumb rule in any of these problems. Is that clear now? So now we are going to take few problem a cord is wrapped around, wrapped twice around a capstan at A and three times around second capstan at B. Finally cord goes over a half barrel section so that is the half barrel section and supports a mass m of 500 kg okay. Now the question is what is the tension T required to maintain this load? Now only thing is that what is being asked what is the tension T required to maintain this load or what is you can also ask what is the range of values of T for which equilibrium is maintained okay. Now to study this problem we should understand that there are two scenarios possible what are these two scenarios? One is the upward impending motion of mass that means we are actually trying to lift the mass up therefore I have to first understand the T must be greater than the weight of the body here. The final T that you get should be greater than the weight of the body here. So this will be always your large tension side okay. So now to get the minimum value of a tension that means we are simply trying to hold the load that means load is trying to come down now okay. So in that case my impending motion of the mass will be downward therefore we can say that in this case the tension in this side will be greater than the tension that you need here. So that means mg has to be greater than that of T. So remember now how do you understand the problem in terms of the force concept whether do I have a statically determinate problem or not that is the first key. Remember here the assumption was always that the belt that is the rope is always going to be a rigid body okay. Now we try to understand this like this way that if I have a tension here my tension will be different here then I have another tension here I have another tension here. So how many problems how many unknowns I have the number of unknowns I have 1, 2, 3 that means tension here, here and here remember tension here is already known because that is simply going to be the weight. So therefore I have to repeatedly invoke the friction laws three times my friction law now becomes T2 by T1 equals to e to the power mu s beta. So I will apply that repeatedly between this tension, tension on the left side of the capstan A with the tension in the right hand side of the capstan A. Similarly left side of the capstan B with the right side of the capstan B and left side of the barrel with the right side of the barrel okay. So I have to really derive these three equations in order to get the ultimate tension that is required. So as such it looks very simple to us now so what we are going to do firstly remember that we must find out what is the angle of contact as we have seen that rope here the rope here rope is wrapped twice here right. So the angle of contact will be 4 pi here rope is wrapped three times so the angle of contact will be 6 pi okay and what is the angle of contact in the barrel it is simply pi over 2. So first we understand what are the angle of contacts of the belt with the respective objects. Now we try to draw the free body diagram as I have told that you can see I am I am interested really to find out what is T here right. So T1 and T so I have one unknown the tension here tension here this is two second unknown third unknown is T2 okay. So I have three unknowns in this problem and I am going to solve it. So how do I solve it now? First assume that impending downward motion of the mass so that means you are simply trying to hold this mass the mass can try to go down. So we are simply trying to hold this mass by applying the tension T. So therefore we can use this relationship one at a time so in this case therefore what is happening this tension has to be greater than this tension. So mg by T2 should be e to the power mu s multiplied by beta of the barrel of the pulley okay. So ultimately what you have this tension is greater than this tension okay. So this will now in the formula becomes T2 and this is actually T1 so mg by T2 then this tension has to be greater than this tension. So here T2 by T1 so this is higher tension side so T2 by T1 is equals to e to the power again mu s and beta what is the beta? Beta is 6 pi because the rope is wrapped around three times. Similarly this T1 must be greater than the T so we will use this one then only thing I have to do basically multiply all of this so that I get a relationship between mass and the tension that I am trying to find out. So the final tension will be this. So if I do this problem by saying now I am trying to pull the object up okay that means now I have to understand that impending upward motion of M that means now friction force will change the direction. So now friction force will all be you can tell like in clockwise in this case okay. So therefore I can clearly tell that this side will have lower tension than this side. So now this side is always going to have higher tension so now I have to just rearrange all of this. So as I said the above relations should be reciprocated. So here we already have relationship T equals to Mg to the power negative the total this thing 1.05 pi so we will just reciprocate this relationship why? Because now I have T greater than Mg okay. Now on other words you can actually flip all of this equations just flip all of this reverse all of this equation same answer same result so what is happening now since we have reversed it so you are going to get very large value of the T you can see that it is so high compared to when you are just simply trying to hold the load you are simply trying to hold the you know mass such that it does not go down. But when you are trying to raise the load right when I am trying to raise the load upward then I need a very large amount of tension in the row okay. So is there any question so far? So if this concept is clear then we can go ahead any discussion on this issue short discussions. Hello 1.17 yeah go ahead ma'am. Sir actually I wanted to ask about the coefficient of static friction and coefficient of kinetic friction there is a general notion that the coefficient of kinetic friction is greater than the static friction. So are there any conditions where we can get the both the coefficients equal or the static coefficient of static friction is greater than the kinetic friction? No no there is no such rule actually see that is not always true actually what you are saying that kinetic coefficient of friction is greater than static coefficient friction I looked actually that is always hold goods okay. So that we need to clarify that first okay that may not be hold true first of all. So secondly see why this static coefficient of friction and kinetic coefficient of friction in one case there is no relative slip between the surfaces right that is participating when we say static coefficient of friction there is no actual relative slip but kinetic coefficient of friction when there is actual slip. Sir there is one more question from today's lecture. So what is the difference between V belt and flat belt friction coefficient? So okay now your question relates to that is a very natural question comes into mind that what is the difference between a V belt and the flat belt right. Now I will try to you know everyone understood the question the question was a flat belt and a V belt. Now V belt will only you know introduce one more you know unknown to the solution. So one more force to the solution rather to solve the problem okay. Now how that will happen? So remember I have to now draw it okay so in the V belt so first let us say when we are discussing flat belt seen flat belt now you are really looking at the cross section of the belt okay. Now in the flat belt case if you look at let us say cross section and try to look at from this side the cross section is rectangular in shape right okay. Now in case of a V belt now where that is applied if you look at the you know the cross section of it. So the cross section will look at so it is on a groove actually the belt will now be on a groove and this is the cross section okay. Now what happens due to that let us say I have an angle V here because it is a V shape right that angle first I have to define so that angle let us say alpha. So what will happen there will be additional reaction that is coming into play let us say delta R from this side and this side okay right. So what will happen now this has a resultant these two if you take the equilibrium you can show like this so ultimately what is happening you have delta R 2 delta R is in that. So what happens now we discuss this problem now so now in now you go back to your flat belt case so where we have looked at only this now here I had a perfect delta N right I have T 1 I had T 2 sorry this will be T plus delta T that is the differential element I am choosing. So basically that effect will come into play so this is T this is T plus delta T. Now in addition to that what is happening this force will come into play which is given by the cross section if you look at this which is given by the groove onto the belt and that will come in your perpendicular equation of equilibrium okay. So in addition to that I am also going to get another force that is coming from the V belt clear. So problem can be solved still but we are not going to take that for the time being but is that concept clear that how this force is coming into the free body and it can be solved okay. So you will just going to get another additional alpha in the equation. So therefore this alpha will come now into the equation okay it will come I think in terms of sin alpha alright. Any other discussion? Sir is there a difference between the friction coefficient of V belt and flat belt? See coefficient of friction is determined by the two contacting surfaces right it all depends on there is nothing your question is there a difference between the coefficient of friction of flat belt and V belt the answer is no coefficient of friction is not but what usually is written in the book is as follows as I said in the equation I cannot really recall the equation correctly but for V belt I think it is something sin alpha by 2 that comes into play okay. Now what we tend to say that this multiplied by the this. So basically mu s sin alpha by 2 that is for the mu s you know of the V belt I think that is what you are trying to ask is there a change in the coefficient of friction between the flat belt and V belt. My general answer is there is nothing change in coefficient of friction but it is how you are writing it. So basically I am now saying mu s sin alpha that becomes the effective coefficient of friction in the V belt okay. Thank you sir. Yeah go ahead sir. In linear motion we consider f is equal to m into a but in rotation we consider tau is equal to moment of inertia into alpha just few days before we have thought that moment of inertia is a task of resistance but in linear motion we consider mass is a task of resistance. Now you are going to a completely different aspect remember so your question is how the inertia comes into play your question is mass times acceleration and I times alpha. Answer is very simple I said I am taking only problems involving constant velocity okay. Even if my drum and the belt are rotating they are rotating at the same angular speed okay. So when it is a constant velocity problem then again you can go back to Newton's first law. So therefore you can again use static equilibrium equation. I am not taking any problem that will involve dynamic but think this way, think this way just simple experimental demonstration okay. I am rotating a disc, a disc is being rotated so I apply some couple right to rotate the disc. I ask someone just put a belt on top of that to decelerate the motion what happens how do I solve that equation of motion. So now what it comes now the belt that you are really trying to decelerate the system belt you are holding tightly right to decelerate the system and therefore now the angular acceleration right that will become a decelerating body. Now if you take equilibrium of that there you are going to see I alpha. So I alpha that is going to come into play and then you have t2 minus t1 multiplied by the distance that is the torque. So that torque is actually going to equals to be equals to I times alpha. Now you are coming to moment equals to I times alpha. So now you solve for that alpha is that clear okay. So problem is very simple whether it you are solving a dynamic problem or whether you are solving a static problem. Remember constant motion problem is itself is a static problem you can actually define it as a static problem okay. Sir actually F is equal to m into a it means Newton's formula is valid only for inertial frame of reference. But we consider in a professional but in professional there is a dynamic in nature then how can I apply Newton's formula. What is here Newton why cannot you see if you are in a non inertial frame then you will simply use the D'Alembert's principle and that I am going to discuss when we talk about it. In non inertial frame means that means you are actually inside that rotating you know you are actually inside that moving body. Then what happen your resultant force still becomes 0 okay. But in a inertial frame how you write it you write force equals to mass times acceleration. But in a non inertial frame you will write force negative mass times acceleration equals to 0. That means there is no relative motion again if you are in a non inertial frame okay. Thank you sir. 1, 1, 4, 5 go ahead for your question. Is there any friction between the center screw of the pulley? In the width with respect to what? Sir in the center of the pulley there is a screw no. Is there any friction between that screw and the pulley? Good question actually yes so your question is is there any friction between the screw or the hinge rather right hinge and the pulley what we have done so far yes no we have not taken that into account okay. Yes sir. So we will see that in journal bearing problem do not worry okay it will come into play. 1, 3, 1, 4 go ahead for your question. Sir will you please explain the concept that flat bulk can be used for a very long center design whereas V bulk is limited to 1 meter only why is it. Yes so your question is what would be the specific applications of the flat belt and the V belt yes absolutely correct. Related to. So it relates to the applications we are talking about okay usually you have a flat drum you know and you will always prefer to have a flat belt on top of that but let us say you have a groove right on the drum also. Yes. Then we are going to use the V belt right so V belt is basically put in a groove. So drum will have to have a groove okay or the rotating system has some threads or grooves there we are putting the V belt. So there will be additional force that is coming from those you know thread or groove okay. So the next question is if I use the V belt in a flat pulley what will be the reaction. No there will be no reaction because there is no nothing there no see in a flat pulley so it is basically a 3D visualization you have a flat pulley and I have this belt now if the flat if there is nothing on these sides right of the pulley okay then I am not getting any force from that side okay. So if the V belt is used in a flat pulley it makes the same thing we are going to solve the same problem T2 by T1 equals to e to the power mu s beta. So problem will remain same okay. Thank you sir thank you. 1, 3, 3, 0 go ahead for your question. My question is how to solve questions in which anything about the motion of the body is unknown. When we do not know whether body is impending having an impending motion or not at all or it is moving on the on the other surface whether anything about the motion is unknown. How to solve questions on that? How can that be you are applying the load right see your question is actually I have to restate that if raise the question so your question would be I am applying a load on a body how do I determine that whether body is under static or under dynamic condition right in a friction problem see remember friction force is a barrier it is a barrier right you are trying to break that barrier okay. So you keep think of it I have a you know a block let us say I have a block on an inclined okay. So I am trying to apply so first I start applying the load small small load I am applying right at some point of time you know when the load is small equilibrium will be maintained that means you can actually use the Newton's first law that resultant force equals to 0 right. Remember friction force is also you know if you plot that that was done yesterday itself right so you are going to also gradually you know friction force is also increasing but friction force has a limit that is mu s multiplied by n right. So as soon as your actual force that exceeds that mu s n then the body is in imbalance condition okay. So you have broken the barrier of the friction so friction barrier is always mu s times n remember that is based on the concept of point friction now when we say it is a dynamic that means you have broken the barrier now we do not know you know body is under some acceleration or deceleration depending on the problem then you have to use the dynamic equation force equals to mass times acceleration or force equals to or moment equals to I times alpha okay. So to decide whether it is under static or dynamic right it is given by the whether the resultant force on the body was 0 or non-zero okay if the resultant force is non-zero then of course it is dynamic that is all simple. Sir we have one more question yes sir why we take angle of contact in radian. Why do because that is a mathematical problem no you are saying your question is why beta is taken in the radian because you are e to the power mu s beta no beta has to be expressed in radian otherwise it is does not make any sense okay it is a mathematical problem. Sir is there any difference between angle of contact and angle of lap or it is the same thing what was that angle of contact and angle of lap I do not know personally I would not be able to answer it okay I do not know which problem you are talking about but that is irrelevant I think. Sir my question is what is the role of kinetic friction in torque transmission see it is of course important see why your question is what is the role of kinetic friction in torque transmission think of simple way think of you know a thrust bearing end bearing problem right if we have a end bearing let us say you are applying a thrust but I also need a couple right if it is rotating body I need a couple okay. So what is happening is that we have resistance from the end right that is coming through the kinetic coefficient of friction because resistance to that you think of disc brake problem I just gave an example disc brake in the disc brake right that brake problem it is under the motion right. So ultimately it is determined that what is the kinetic coefficient between the belt and the disc that will able to either decelerate the body right. So deceleration will depend on what is the kinetic coefficient of friction but not only that remember the contact angle here also plays an important role what is the contact angle that is also determined and we will come to that problem the question that you are asking the kinetic coefficient of friction if there is an actual slip between the belt and the drum right then how that torque is actually changing okay. So it helps it helps the you know changing the torque definitely depending on the coefficient of kinetic friction we have. Another question is which types of precautions should be in mind before designing the right flat belt or when you are designing a belt let us say the two things are very important coming into play of course as we have seen here one is the coefficient of friction and that was your in fact earlier question okay kinetic coefficient of friction. So that one thing another is definitely it is determined by the contact angle okay. So these are the two aspects that we should look at when we are looking at the force I am not getting into the other part of it. So if your question is related to more of a design then I am not answering to that but more or less if it is related to force right these are the two things controlling the force okay transmission of torque if you say like that then these are the two things basically controlling okay. One three zero five go ahead. My question is the problem with your just all on belt friction there you have taken that wrap round and three wrap round and two wrap round the angle of lap you have taken six pie and four pie can you elaborate separately by drawing that particular freeway diagram and can you justify how it has come six pie and four pie. Yes so the question that we have received from one three zero five that contact angle that we are saying one is wrapped around two times another is wrapped around three times. So if I have a two wrap and I simply explain it I do not see one let us say one time let us say one time wrap then what that should be if it is a one time wrap that means let me draw it here okay. So what does that mean that is it that is a one wrap so you go yeah that is two pie right no one wrap will be two pie one wrap means we are going to make full revolution right okay so that means that is it okay so that is one wrap so I go like this and then come back like this okay then two wrap put this one actually okay so you go around then one more then another okay so two full revolution right remember at the look at the problem there you will see that going like this and then exiting like that right so that makes it one wrap if you have two wrap then you have to wrap it around two times okay so just make two full circles that is all okay so one full wrap will be two pie two wrap will be four pie and three wrap will be six pie. Sir what happens if I change the geometry from circular to rectangular? Your question is you want to change it from circular to rectangular but why why why do you have that question in mind? If I take the rectangular material rectangular geometrical shape nothing will happen it is just going to get more complex because now you are going to see that you have three sides your question is if I have a rectangular segment let us say let us say not proper rectangular you have some kind of you know fillet shape here okay so now you have a belt now it just you see that what is happening as I said friction is always going to you know gets complicated because now you have to look at this part that part and this part three parts has to be separated and look into a different manner and problem gets more complicated okay because remember what we have done in case of a flat belt on a drum right we have always considered this small segment okay and we try to establish the force was delta f equals to mu delta n right so we have again applied the concept of simple friction to go to the complex friction we have to integrate in this case it is even more complex but remember this you will not see any physical problems a physical problem will always try to address a nice circular you know a drum or a pulley again it will determine it will be determined by the free body diagrams and how you take into account can you explain it again why angle of contact taken in radian angles are measured in radian you have log log value log t2 by t1 equals to mu s that is going back to simple math class you have log of t2 by t1 equals to mu s beta right now you are saying t2 by t1 equals to e to the power mu s beta so therefore beta should be measured in radian okay 1, 2, 9, 3 go ahead why you are not consider the centrifugal tension in the flat belt and v belt your question was why the centrifugal force was ignored I did get that answer when I was discussing two ways one is the center of you know the mass of the belt could be small that is one thing second one was the answer could be the rotational speed is not that great or in other words the belt will not detach from the drum or the pulley okay we can just think of that way if the if the rotation speed is very high then we may have to incorporate that. Sir one more question sir in the v belt there another term is cosmic beta is coming if someone book are given cosmic beta yes 1 over sin alpha that is what it is okay 1 over sin alpha that term I tried to explain that before also no sir I am asking to you that alpha for the lab angle right and beta for the v angle that is what it is that is what I am saying so you have e to the power mu s beta so beta is the contact angle okay lap angle right and then there is another term which is sin alpha by 2 I think 1 over sin alpha by 2 that comes from the v belt that is from the cross sectional direction that is coming into play okay so there are two terms okay that is coming into play yes we will now start little bit more you know getting into problem specially you know we should try to look at belt drives type of problem how to you know look at belt drives okay now this is another interesting problem we are going to study that involves both static coefficient of friction and kinetic coefficient of friction okay so now how this is happening a cable passes around 3 2 inch radius pulleys and support two blocks as shown so in this problem there are three pulleys remember two of the pulleys d and e are locked to prevent the rotation okay while the third pulleys rotated slowly at a constant speed just pay attention to this that they are rotated at a very you know this third pulleys e is rotating at a constant speed so we know the coefficient of friction between the cable and the pulleys determine the largest weight which can be raised if pulleys c is rotated clockwise that means we are interested in finding out the largest weight that can be raised when this pulleys rotated very slowly clockwise again this is rotating at a constant speed therefore remember the belt and the pulleys they are intact so belt is also have the same angular rotation as that of the pulleys okay now in this here belt is actually constantly slipping over these two pulleys so the problem involves therefore we can clearly see the two determine the largest weight that is possible two days we need to invoke the impending motion condition at c right so for the impending motion you can clearly see the largest weight that is possible will be based on when this belt will try to actually slip over the c so when the belt is trying to actually slip okay just about to slip over this pulleys then we will say that impending motion is reached and therefore I will be able to obtain my largest weight that can be lifted up now again it will involve drawing the free body diagram of each and every pulleys remember there is a kinetic coefficient of friction is coming into play in drum D and drum E should have the kinetic coefficient of friction because the belt is constantly slipping over this pulleys so ultimately you see that to decide this problem we first make sure that where the impending slip has to prevail because it relates to the largest weight see the largest load that is possible if we ask always this kind of question then impending slip logic automatically comes into play the other drum the belt is constantly slipping right so no problem here we can simply use the kinetic coefficient of friction in this problem so now we have to really look at the free bodies specially we will be concerned with the belts so you can see the tension on the belt side we have to be careful that how the tension starts to turn which side would be greater and which side would be lower one more thing to understand the contact angle that is very important so the contact angle that we can find from the geometry of the problem so first we decide on the contact angle and we express that in terms of radian again so all the contact angles are shown here now remember the C is rotated clockwise as I said therefore which side the tension would be higher in this case if it is rotated clockwise and if I try to look at the free body diagram of the drum itself how the torque has to be transmitted see you are applying a torque which is not given actually a torque is applied clockwise to balance that this side of the tension has to be greater than the other side of the tension so w a must be greater than this side so tension in this side has to be greater than the right hand side so therefore now this is becoming T2 and this is becoming T1 so we say that w a is now T2 and T2 itself becomes T1 okay so this is the higher tension side this is the lower tension side and it is very easy to understand also because I am rotating it clockwise and to balance that torque ultimately it has to be balanced by the opposite torque that is given so w a minus T2 multiplied by r that will try to balance that torque okay similarly so when I express this relationship then I go to the next one the next one will be now we decide which side the tension would be higher now remember the belt is constantly slipping over the pulley so the slip direction is already defined slip direction in this drum D and drum E is already defined therefore I know the resistance direction resistance friction will always be opposing the motion so friction force direction is already known if I know the friction force direction which will be clockwise in this case therefore this side tension on the right hand side tension will be higher than the left hand side tension so now you see in the formula I have to see say that T1 is actually higher than T2 and I have done that based on the fact that which direction the belt is slipping there is an actual slip between the belt and the drum remember drum is fixed belt is constantly slipping at a very slow speed so therefore I am going to use T1 by T2 equals to e to the power mu k beta so I put that this is another expression and the last expression as we can see here that again the same logic will be applied this side tension will be greater than this side tension because there is a slip here right and frictional resistance is coming on the other direction counter clockwise in this case right so this tension will be greater than this center so I use this formula 16 by T1 so 16 by T1 should be equals to e to the power mu k beta therefore now what I have I can now solve these three equations right to get a relationship between ultimate objective is to find out the WA which can be achieved by the similar process we have done so the value of WA the largest weight that can be raised is 11 pound okay so now this problem involves using both the two points both static coefficient of friction as well as kinetic coefficient of friction remember problem can come in variety of ways but here again we are trying to study from the point of view of equilibrium and we are trying to invoke the friction law as required so here we have a constant velocity problem constant velocity means a couple is applied right and there are four we are trying to see when this slip is trying to you know when this belt is simply trying to slip what is that condition that will be my impending slip condition right then we looked at also when slip is actually happening that is there is relative slip between the belt and the pool.