We are going to be talking today about scientific computing with Python and it's really fun to see how the community has grown and how much is going on these days in scientific computing, specifically with Python. There's a conference this year that is really, I guess we're probably in our sixth year now. And so if any of you happen to be in Caltech next month, we'd love to have you at the SciPy conference. This is a group that's been meeting I guess since 2001 or two. I can't remember when we initially started, but it's specifically for really the scientific community. SciPy, as we'll talk about a little later, is a package of libraries or toolkits for doing scientific computing. But the conference is really much larger than that. People come and talk about all kinds of different things from astronomy to genomics to neuroscience. So it's an interesting place to go and listen to talks. So please consider that if you're in the U.S. So what is Python? One of the questions that comes up is how many people here know FORTRAN? Y'all use FORTRAN. How many are C++? How many are MATLAB? Yeah, so there are all these other languages out there that actually have been used for 20, 30 years, some of them, in scientific computing. Why are we switching, or why has there been this large shift to using or to looking at the languages like Python? I guess there's not been a large shift yet. There's still, those other languages still dominate the landscape, but Python is really growing in popularity. Why is that? Well, I think it was, well, I can't remember the person that actually came up with this one-liner. It's the Python programming. Mark Lutz is the guy's name, I believe. And he had a quote that said something along the lines that Python is strong because it allows you to do everything that you can do in a compiled language like C, C++, or FORTRAN, but it's a much simpler language. And that's largely true. In the scientific world, you know, there are places where we run into where Python isn't the choice, but when that's true, then we can, it turns out, Python interfaces very nicely with these other high-performance languages such as C and C++. Now, you're not going to sit down with Python and probably write an operating system.  But most other things that you look at, you know, if you look at building a tool for network analysis, or for writing a network-based program, or writing applications for database queries, things like that, well, Python works really well for all of those. And there was even, there's a guy named David Beasley who was contemplating, and he may have done it. He taught at University of Chicago, and he had his students implement the TCP IP stack in Python. So there's not a whole lot that you can't do. Sometimes it's not the fastest choice. But it really works well for these things. And because of that, Python has this huge breadth of capability. And if we can add the scientific side to it and get the libraries in for that, then we have this wealth of capability that we can add to having very rich applications and scientific computing. Hopefully you'll see that over the course of the class. So what are the things in Python that make it really strong? Well, you know, automatic garbage collection is a major feature of a lot of languages these days. Java and Ruby and Pearl, all of these languages, if you've, I think a lot of people raised their hands with C and C++.  And there's one, I think it was Eric Raymond who made the comment that probably 80% of the programming errors that come up in applications in these languages are from these memory errors and the effort that goes into fixing them. So if you can avoid that, it's nice. Now Python's not perfect. You're going to end up with memory leaks in programs that you have to chase down. That occurs. You have to pay attention to your resources. That's true in all of these languages. We haven't come up with a utopian garbage collector yet that works for all problem sets well. But it works very well. The other thing is dynamic typing. And this is a critical thing for scientists. When you sit down, you know, scientists are really worried about problem sets where at the end of the day, you don't know where you want to be at the end of the day when you start the day. You have some data set. It's in some file format. You need to read it in. And now you're going to do some analysis. Maybe you're doing statistical analysis. Maybe it's a signal. You read in the signal. You plot it. What does it look like? You take an FFT of it. What's its spectrum look like? Ah, there's some noise up here or noise. I need to filter that out. Now I have some colored noise in some area that I can notice. I want to filter that out and look at the signal. And so, you know, there's this process of not knowing where you want to go. Well, the dynamic typing and the interpreted and interactive notions in Python are really critical to this. You can import your data. You can sit there and play with your data. And you can say A equal 1. And then A a few minutes later can equal array. You don't have to think about, oh, I've defined all these variables as a specific type. It allows you to play with it very quickly. And then the interpreter is critical because you can interact with your data very comfortably. So both of those are really important as scientists. And really this is, you know, MATLAB came after C and C++. MATLAB had a lot of strengths as far as having vector calculations and that sort of thing built in. But I think one of its major strengths was that a scientist could sit down. They didn't have to type their very specified types on their variables. They didn't have to write a compiled program to run and analyze their data. They could sit there at the command line, type things in, see the results immediately. Python has that same strength. Another major strength for Python is its object-oriented design. It's really object-oriented from the ground up. It wasn't an afterthought that was added to the language. And, you know, a lot of these, the features like dynamic typing and interactivity are really critical to the scientist and in exactly the same way the object-oriented notions are very critical to the computer scientist. And this is a major importance to the scientific community because we do write a whole lot of things where we don't know where we want to be at the end of the day and we mess around with their data and play with it. We come up with some interesting algorithm. But at the end of the day, once we have that interesting algorithm, we don't want it in a script that gets passed around the world. We want to create an application that this lives in that has visualization, domain-specific objects that people can work with, a nice interface, all of these sorts of things. To make it more useful to end users. And to make that happen, typically we need the help of some software architects to come in and build out this larger framework for an application or around our algorithm. You know, if you look at applications, I worked in electromagnetics and there's an algorithm called the finite difference time domain algorithm and it will run for days if you want it to or need it to to calculate what the radar cross-section of some object is or what the properties of a circuit are, what the radiation of an antenna pattern is. And it will run a long time. I mean these take days to run on large problem sets. The code base for a typical problem set or for a typical empty TD algorithm, I would guess is somewhere between 10 and 50,000 lines of code. And if you look at the algorithm, the algorithm is about 50 lines of code. It's very, very small. And so all of this other stuff around it is really the pieces that you use to read in files to allow a user easily to set up the problem to post-process the problem, that sort of thing. Well, all of this stuff around really needs, if you're going to have a maintainable long-term application, it needs to be built in a robust way. And one of the tools that's currently used heavily in computer science for building these sorts of architectures is object-oriented programming. So that's a critical piece. The notion of batteries included has been talked about quite a bit in Python. And I think the library is probably going to shrink a little bit the standard library as they clean up some of the pieces. For a while, the notion was this battery is included is Python comes with every library you might want to need for your application. So if you look at the standard library, there are all kinds of tools for URL live and email tools and telnet tools and things to deal with accessing pieces of the file system. I think the library is probably 80 or 100 libraries now. But some of those also deal with libraries crept in that deal with the audio format for SGI computers and things like that. Well, so they were probably a little loose in the beginning with the number of libraries that got in. Now they're going to start trimming those out as time goes on. But that huge library of capability is really an important notion because you get out of the box something that really solves a lot of problems. Free, I think, some places that's not very important, a lot of places that is very important. Matlab licenses are expensive and mathematical licenses are expensive. It's very nice to have a tool that if you build your application, you can send it to anybody and they're able to grab a piece of software off of the net and run it. So I think that also, you know, that's one of the reasons Python has grown as well. It's hard to be free on price. Portability is another reason it has grown very quickly. Python runs on this. You know, you can run it here. You can run it on the big iron machines that come from SGI and from IBM as well. A lot of national labs in the U.S. are running Python on their supercomputers. So portability is important. I had this notion in grad school to point out how easy it is to learn or use. You know, I wanted my advisor to be able to read my algorithm. He may not be able to read the application, but he could read the algorithm and understand what I was doing. And so one of the questions was when I wrote a computer program, could I show my advisor and we'd be able to talk about it and Python passes this test. The syntax is easy to learn and understand. There's not a whole lot that gets in the way where you have to learn what a lot of different symbols mean. The other point is that it has a very nice and elegant numeric syntax for doing vector cooperations on arrays. And we'll talk about that tomorrow. But that really helps in the scientific community. And then the modularity of things. Python encourages you to build code that is modular so you can build these libraries that get handed around and used in this modular way. And modular programs not only are easier to reuse, they're easier to maintain over the long term. So that's kind of an overview of Python itself. And I guess why we're here today to talk about it. The course from here today we're going to focus on the language itself. So today we'll focus on the language itself, get everybody up to speed on that. This afternoon we'll have hands-on laboratories, which will give you an opportunity to sit down and work through problems. Prabhu and I will be there to help out as we work through the problem set. Just to give you an idea of who's using Python, one of the major first users I think was the Space Telescope Science Institute. Those are the guys that process images off of Hubble. And so it's used in really the pipeline for calibrating their equipment and also processing the images off of the telescope. And maybe a slightly different area, Hollywood, is also a major user of Python. And all of these companies are using it. It's funny to go walk around the Python conference and you'll see Spider-Man t-shirts or the Hulk t-shirts. But the place where it comes into play, these companies have very large rendering farms, right? I mean, they have hundreds or thousands of Linux machines usually in some back room. And each of those machines, once somebody has set up a computer-generated graphics scene, each of those machines will be in charge of rendering one frame. Well, the process of splitting all of the information out to those machines and managing that is often controlled by Python. There are also tools for doing the masking and putting together if they created a scene that's computer-generated and they need to put a person in, then the process of how that's done is often done with Python. So it's kind of interesting that it's there. It's also heavily in the geophysics industry. We work a whole lot with ConocoPhillips. There's also Shell. Saudi Aramco uses a little bit. And so it's starting to work its way into that industry. Google has hired Guido Van Rossum. Alex Martelli is there. There's a number of people out of the core community at Python that are actually... Guido is the creator of Python that are on the Google staff. And Greg Stein in one of his talks, I believe it was at Ascon, talked about the usage. And he named C++ and Java and Python as the three most heavily used languages there. So that's another area to use quite a bit. I was interested to see that PaintShop Pro in their version 9 came out and they chose to use Python as their scripting language. So we're all used to probably Excel and Word and these languages are these applications. Well, you can always script those applications with Visual Basic on the back end. Well, Python was embedded by PaintShop Pro, not maybe in the most transparent way, but still it is the scripting language that they use to drive their application. And that's a really good use of Python. I hope to see more languages over time that really have Python as their scripting engine. And we really want to encourage you to use it as the scripting layer for your scientific applications. If you've ever loaded a Red Hat installation, or at least this was true in the past, I think it's still true. One of the very first things that was installed is Python. Because Anaconda, which is their installation application, is a Python application. So it runs through. And then Procter and Gamble, we also work with them quite a bit on building fluid dynamics applications. And these are applications that have a whole lot of, they have CAD that has to go through meshing, that has to go and run on a supercomputer and then come back and be visually analyzed and the data needs to be processed. And then somebody needs to change the initial design of an application, of whatever they're building. So that's very common. I think there may be quite a few people in here in the fluid dynamics world. And so it's commonly used there. I became interested in looking at these graphs that Tim O'Reilly produces. Tim O'Reilly is the, or I guess at least analyzes, that Tim O'Reilly is the publisher of the O'Reilly computer books. You may have some of the books that have the animals on the front, their computer programming books. And he has a blog, and I think it's about every quarter. He does a reanalysis of languages. And this is all data from Nielsen. All the people in the U.S. have a, or some people in the U.S. have a box on the top of their TV that records what they're watching all the time. Nielsen takes that information and analyzes it, and then that's used by the advertising industry to figure out which kind of toothpaste people should buy or whatever. Who's winning in the market segments? Well, they do the same thing with programming books, or the book market in general. And so one of the things you can do is go through Nielsen records, what books have been sold every quarter. And I think O'Reilly has post-processed this data in a way where they can say how many Java books were sold, how many C-sharp books, how many, and the way they do that is they just look for the name and the title, or maybe in a brief blurb on the book. So if you were looking for the popularity of the language, this isn't a perfect measure, right? I mean, this is a proxy for what we're actually looking for. But it's a reasonable proxy. It's a nice little tool to look at is a language growing? Is it shrinking? What's its market size? So if you look at this plot, what we have is the whole rectangle is the whole market. And then the size of each rectangle is showing you the size of that language's piece of the market. And so you can see that there's some, the usual suspects are kind of the big ones. Maybe Visual Basic isn't one that we might think of from the scientific community, but if you go into corporate America or corporate India, guaranteed you're going to see Visual Basic runs the back office of half of these guys. You know, it's heavily used on setting up reports and that sort of thing. So Visual Basic is a major tool. Java has the largest chunk, not surprising. CC++ has a huge chunk. And PHP, that's a language that's heavily used on the web, really grown in popularity and has a large chunk. And then JavaScript is a huge piece. And not only is it a huge piece, but the colors that you see here and then the percentage number there, Java negative 14%. If it's red and has a negative percentage, that means that the market share from last year to this year has changed by that much. And so we can see that Java, even though it's the NC++, even though they're the big languages used, they're shrinking in popularity, at least if looked at from book sales. On the other hand, it's fairly believable that JavaScript not only is large, but it's growing very quickly. And this is because of the web 2.0 push with all of the Ajax and interactive web browsing capabilities. So that's critical. So we have kind of the old guard languages, mainly up there that are large, a few new ones that are growing that are also large. And then you kind of see this green kind of band across here. And those squares are getting bigger, and those are languages that are kind of the new guard that are coming in. And C sharp and .NET languages are a huge part of this. So that's some partially a testament to how strong Microsoft is and the size that they have in the marketplace. But C sharp is also a very strong language. And so that's another critical aspect of that. It's nice to program in.  And how many people have used Ruby are seen? So not a few. Ruby's heavily used on the web. It's a general purpose language, but the reason it's really caught fire, JavaScript is kind of driven by this Ajax wave. Does anybody know what's driving Ruby? Ruby on Rails. Ruby on Rails, exactly. So Ruby on Rails is just pushing its growth through the roof. It's not only has a large market share there, but it's also growing very quickly. So that's interesting to see. And Python is sitting over there, and it's similar, smaller market share and smaller growth than Ruby, but still in a very nice place. I mean, it's on the vanguard of the languages that are up and coming. And Pythons, you know, one of the nice things to think about there is that it doesn't have, it's not being powered by something that's in vogue right now. There isn't an application that's fueling the growth of Python. Python's strength is really very general. I mean, we're going to sit here and talk about scientific computing. There is a huge portion of the Python community that has no clue that Python's even useful in the scientific computing arena. It's really, they're just using it to... There's a company called Rackspace that uses it that has thousands and thousands of servers that you can... You just call them, they'll set up a rack for you, a server, and they'll co-locate it at their place. Well, their whole system is managed with Python. They don't care that you can do numeric processing. They just care that they can have a distributed system that works well. So there's this very wide range of users and really that growth is very broad and that's very important to, I think, the long-term health of the language and where it's going. And I want that to happen because I want the people outside of the scientific community using it very heavily so that I get to use their tools in my scientific applications.


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And it is a spot where it causes some problem. So we've looked at the kinetics of pure translation of rigid bodies where now, even though the object is not rotating, it still has the effect of some moments that can cause changes in some of the forces. We looked at that in the like the airliner problem we looked at where because the thrust of the engines was not directed directly through the center of gravity, it caused a change in the reactions on the landing gear of the aircraft even though there was no rotation of that aircraft during the taxi. Then we also looked at just pure rotation where objects were not subject to any kind of translation at all, just rotation. Now we're going to put the two together and do general plane motion where we have the possibility of both translation and rotation going on. Of course the easiest example is a tire rolling on the ground. Either with no slippage or maybe with some partial slippage, it could still happen. But the point is that the wheel, the center will translate to some other positions and the angular position of the wheel will have changed as it rolls. The compound nature of both of these usually too are looking at acceleration. So there'd be acceleration of the center of gravity but also some kind of angular acceleration. And so we'll look at a couple of things with that today. The basic idea being if we've got some object subject to several forces and all kinds of things are possible into several moments of some kind in some direction and the compound effect of those is going to be some angular velocity perhaps some angular acceleration and some translation of the center of gravity wherever that might happen to me. So if we then, oops, can't have the thing change from yellow to pink the compound effect of all of those is such that the forces will cause some bulk acceleration of the body. In effect if we put it in true kinetic terms we might have m times a. So essentially the net force there might be some net acceleration as well. So we have the three equations of motion. Subscripts. Do the same thing in the y direction. Those components are the pieces of this resultant vector in whatever coordinate directions we need some of the moments also to be then of course resulting in some acceleration. Now to help Alex with the one question he had if we do this about some other point besides the center of gravity maybe about some point p that's no trouble if we know the moment of inertia with respect to p which we may or may not it depends on what the object is we're talking about what other information we might have about it but if we apply the parallel axis theorem to that anyway it then sort of backs it up to the angular acceleration with respect to the center of gravity plus this turn m a g d s the acceleration I had up there and that d is reduced from the line of action of the net force that m a g to that point p noticing too that we need to take into account the directions of these things that this would have an angular this would have this part here would have an angular direction at least as I pictured it in a clockwise direction we have to take that into account with any other moments that are in the problem so there's not anything terribly new there other than what we've got what we've had already however if you're short of equations then you can always add into it any kinematics that are available in the problem such as the no slip condition that's our most common one of the kinematics equations that we can add in there but any of those other ones the relative velocity relative acceleration any of those type of equations are fair game if necessary to solve the problem necessary and useful to solve the problem so let's do a couple problems there's nothing really new up there just we're getting a chance now to put it together so that we might have both angular acceleration and linear acceleration in a problem now okay so we'll look at a type of problem then I'll give you a special in class exercise to see who's been paying attention if anybody so imagine a spool with cord wrapped securely around the outside about a separate cord wrapped around the inside five meters inside only two meters, mass of eight kilograms radius and gyration of 0.35 meters so the spool is made up of a couple of different masses all on the same axis but in general we don't have that type of thing in the book so the radius and gyration is an indication of just how much of the mass is in the interior spool part and how much is in the flanges on the outside okay we want to find alpha we can do it in two ways to help illustrate that very problem that Alex was bringing up and it doesn't matter if we have a general motion problem or any of the other type problems the dealing with it is the same okay free body diagram diagram which is one that essentially shows the net result of what we have going here obviously the two cords exert a force however in that one attached to the ceiling we don't know how big that is that has to be one of our unknowns we do know how big F is though of course it's also got a weight those the net effect of all of those together is going to be some acceleration of the center of gravity so that would be essentially the net result of the force and then we've got to figure if it's doing that because that's pulling that way there'll be angular acceleration in that direction and that's what we're supposed to find how many unknowns? unknown what was the other one? let's assume if we're given mass let's not take weight as unknown because it's just so straightforward if we're given radius of gyration let's not take moment of inertia as unknown because again it's just a very straightforward calculation so we don't know this tension and we don't know the angular acceleration doesn't mean we need to find all three but to find any one of them at least we're going to need three equations what are the three equations? center of gravity is there and that will equal well be specific IGL there's two equations what's the taking the moment of inertia is one of the unknowns so take that as given that's just a straight calculation don't take that as an unknown take that as an equation so what's the third equation? well that's not going to help there are no forces in the x direction so all we're going to have is zero equal to zero so the kinematics equation is available so we need a kinematics equation for useful purposes called that A so what is the equation that we use there? it's got to be an equation that has at least one of these in it I don't want to introduce any more unknowns but that's all the ones we have anyway T will be in here T will also be in here and G is in there and G is in the other one so hopefully something that relates one of the two pairs possible that is as simple as possible because I think that's what Pat was heading towards you have to assume that this cable around the outside is not slipping so it's a no-slip condition and what'd you say, Jay? before you jacosize your answer? it's a no-slip we're assuming that the cable is not slipping and since this part of the cable is not moving itself then what's true about point A? it's what? it's not accelerating well it's an instantaneous center and so that's R1 we can then use that very same type of relation we used before AG is going to equal R1 alpha as a no-slip condition which I think is what you said, Jay, isn't it? so there's your third equation so set up these two equations we don't necessarily need to go through the actual solution of these it's not an algebra class what part is that? or is that totally different? what part did Bob say? that AG first two equations, make sure we got them right Frank, you have to get them over there I'll make them get them over there two components to this one of them involving omega we're assuming starting from rest so that there is no omega at that instant spare your equations won't you get them? forces in the y-direction fairly straightforward I hope plus T they're in the same direction no question about that I wouldn't think W's down that's all the forces and so then we'll have the acceleration of the center mass so there's F equals M in the y-direction if you want you can then put in the no-slip condition what do you have there for WG? I'll remember it's good practice in these to indicate your positive direction so that you can lay these out properly we expect acceleration up to go with a clockwise so that might as well pick that as the plus direction save ourselves a minus sign so what do you have for some of the moments about G then? R2 yeah it would be and W goes the way of course goes right through G IG which is K squared M M times AG I just made this substitution in fact that also didn't do it on that and you can eliminate T between them if you want and I don't need you to solve it that's an exercise in algebra but you should get that was to be 19.8 the weight itself is 78 so not much of the tension not much of the weight is left on that on the cable anymore so that's where the algebra are eliminating T between these two equations leaving you with one equation in alpha and solve for it and fill in the rest from there any questions on that part? I think so because for some it's pretty obvious for this problem that the acceleration and the angular acceleration are in the same direction but that problem coming up where it's not as obvious and it's going to be quite helpful in fact it'll keep you from losing the minus sign if you have that kind of drawing some of the problems are so simple you can just put them on the same drawing you don't need to do separate ones just some kind of different indication of what the acceleration is alright now in direct response to Alex's question let's do the some of the moments about some other point in fact we'll just pick point A the solution in some of the moments about some other point we also have the moment of inertia about that point which we don't however we do have it about the center the moments about point A again we'll take that direction positive we know alpha is going to be in that direction so we'll give us a clean answer we have what moments being caused about point A what moments caused about F F is a distance of both radii away R2 and it is in that direction alright what else W of course in the opposite direction what about is that R1 that's alright and notice we don't need to worry about the tension which is the advantage of doing it this way if you wish it just eliminates one of the unknowns IG we've got K squared M alpha we're looking for but let's see do we add MAG or do we subtract MAG sorry MAGT do we add it or subtract it that's our positive direction about point A AG is going to do with a positive direction it's also going to be in that positive direction with respect to point A and in fact there's the D we need is the minimum distance between the line of action of MAG and that point A this is MAG times D which is also we have the effect of the way in there but it's done this is the sum of the moments this is the result of that sum of the moments okay so I should have like a plus W on the other side nope nope just that and then notice that now you have a single equation with a single unknown alpha the one that was asked for and when you solve that you get the same alpha you did before that helped a little bit Alex illustrating that do you see the advantage to doing this it's not huge but it does eliminate one of the unknowns if the tension had been asked for there might not be any advantage in doing this but since the tension wasn't asked for then there definitely could be an advantage to eliminating it from the problem we're going to do an example with something like a link arm or something nope not yet you've got to a little in the stumble before you can walk in GR that could be negative as well as you said yes if I had chosen the other direction it would have put minuses on those remember this is just an arbitrary choice I chose it that way because I knew alpha would be in that direction and that would give me a positive alpha it's nice if you know that direction so if we happen to have a problem where if AG is that way but I've picked that way is my positive direction that will give a minus MAGD because that's my positive direction the action of AG is against that it's as simple as that we've got another one coming up where it is negative because it's a little bit trickier problem alright any questions before I clear up and give you a mental challenge like you've never faced before you got for it Bob I bet you wish you brought a chocolate egg now there's some energy for a bribe chocolate eggs go a long way to extra credit points that's for sure alright what I've got is a simple simple little spool thing here with some string wound around the and I'm going to do two things and you have to predict what's going to happen both times so first thing I'm going to do is let the string wrap around such that it comes out that way and you need to predict what the spool is going to do and to help with that even though it may be obvious anyway it's going to be a free body diagram yep that's what that means, Jake what else does that mean do you think that T stands for turn around go the other way does that make more sense start from rest I'm going to pull on the string T as shown free body diagram and then predict with it the kinetic diagram these circles just aren't filled in it's going to look like you guys there's nobody right at the center and no value to this you have to predict the magnitude of any of this just predict it's action free body diagram then the kinetic diagram the kinetic diagram is the diagram that has MAG on it which is the sum of the forces and then has IG alpha on it which is the sum of the moments shows what you believe the sum the result of those actions is going to be but he's right so far with the kinetic diagrams oops I mean free body diagrams we got one correct free body diagram get this stuff out of there it is not the object that's why can I not go to the ground do you make these in a smaller frame I'm going to go to the next diagram I'm going to go to the next diagram the correct free body diagram obviously the tension is in there however hard I choose to pull on the cord any others Jake you got something else what else the weight I hope nobody disputes that it's only cardboard Bobby is there any other forces a normal force because it's sitting on the table there Frank in which direction my attempt is to pull it that way friction is going to act in the reverse direction to that to the left so that's the free body diagram what do you think is the kinetic result of that first is t greater than f or f greater than t t's got to be greater than that there's no way friction is greater than the force causing it the sum of the forces will be that way what about the sum of the torques in fact don't we have some of the torques here almost a couple it's not a couple since those aren't the same magnitude but it's like a couple which will have some net result that way the two of those together is most certainly going to cause it to turn counterclockwise you did so anybody have anything significantly different than either of those especially you folks that didn't have the friction and the normal force in alright so let's run the test let's see if I pull this way that's exactly what it does what we think this is so exciting you just never know what's going to happen like being at the science museum look at that that was a beautiful demonstration and did exactly what we thought it was going to do alright fake deal I could ask some dope on the street to help me down alright so let's do the same thing and you predict what's going to happen however I'm going to put the cord on the bottom now so on a free body diagram and a prediction via kinetic diagram of what's going to happen I'm going to pull it so it doesn't slip if I pull it with and it slips and the guy knows what's going to happen I said you were ready then you say you're not finished you got a feeling of what it's going to do Bobby you ready you're ready to lay down your life for this Alan did you finally commit to I'm going to pull it so it doesn't slip so it doesn't slip yeah I said that right I said that to those listening it's kind of soft so it doesn't slip if I pull hard enough the thing will just go like that and we don't have a very interesting problem and we like interesting problems well I need a bigger block in the chair and that's an extra pleasure so when you take this again next year we'll be ready Alex you said alright let's see what the free body diagram looks like of course there's going to be some tension there what else still weighs something I hope there's no dispute in that at the bottom there any friction this time yeah why not otherwise if I pulled on it it would just simply slide along turning it all there won't be some friction which direction yeah there's only two choices right and it's left which direction you said right right you said left left with a question mark imagine it's on not only ice greasy slimy ice the slickest thing known to man absolutely zero coefficient of friction static or kinetic if that was the case and I pulled on it what would it do it would go to the right since I don't have a greasy slimy snotty surface then friction must oppose that so friction must be to the left you got it right and you don't understand it imagine what it would do if there was no friction if I pulled on it it would go that way it wouldn't turn but it would just go that way it might turn a little bit just because the cable's off center but in general it would just slide that way what? no? that means the friction would add to that force it would take off that way even faster friction doesn't do that does it? let's see maybe this will help let's imagine this if you're not buying the no friction argument let's imagine the infinite friction argument let's imagine this is a geared wheel with a rack to the ground there's no possibility of slipping there so if I pull on it that way about an instant center there isn't that a met torque on it that way and it's going to roll who says that's going to that pretty small torque compared to that so if we sum the torques about the center of gravity looking for a sense of these that's a very small torque about G whereas that if we have that kind of friction and that's all the gears could do the wheel gears would push against the the rack gears the rack gears are going to push back that's a much, much bigger torque this one goes that way this one is much smaller and goes that way how is this diagram really any different from the diagram we just had other than the fact that the forces moved down a little bit well you don't mind it so let's see it cable coming out, strings coming out from underneath I pull it lightly so it doesn't slip no it's a magic trick it's a magic trick if you try to impose something on it that's not going to be there if you impose a friction in the opposite direction which shouldn't be there there's a force to the right there must be friction to the left and it takes, it's amazing how little tension it takes to make it move don't do it with just the weight of it off the edge so now what you need to do because you guys are schooled in this and most of you got it wrong now when you're old enough this is a good bar bet right here you don't pick some guy all muscly and you've gotten more money than brains say hey buddy, I'll bet you for a beer which way this will go when I fall really got it right because he doesn't know how to draw diagrams, he pulled himself most people look at that and think a few will say it'll do what it did, most will say it'll roll the other way start with this way, bet him this way and then he gets a free beer and then you say oh gee we better go double enough now and then put it that way and pull it no, what everybody's thinking is that this is the predominant effect and if the cable's underneath it's got to turn counterclockwise but the friction has a much greater torque the other way remember it's the sum of the torques that causes the angular acceleration so if that radius was smaller would it go left like what would we do to make that go left why do we think it's going to go left because obviously for something obviously we've seen something that's done that it's because you can see this force I guess it's because you can see this force and so you think this is harder this is always harder students have always had a little bit more trouble placing the friction when they do other forces there's no question about this once you, if you thought friction was to the left then there's no other possibility but it going that way because we still have this clockwise motion between the two forces and we have the net force that way, oh we didn't do the kinetic diagram there's a plan of the area the sum of the forces has got to be that way then the sum of the forces that way even if you thought the friction was going the other way that just makes two forces going that way and if I said it wasn't going to slip you should have even been more convinced that it would roll for the right like it didn't anyway you can try that if you want just see how easy it is it's amazing how simple how light a force it takes to move that way and you can do it with just a spool of thread too you don't have to have something cool like that is that was my spool we have my kite kite line another problem let's step up here now this one also you may need to argue with your intuition a little bit imagine my truck notice my truck is not pink even though my car is and they look kind of the same there's my truck upon it I have maybe this spool that I was transporting all right give the truck an acceleration let's say 5 feet per second squared the spool is not tied down unsecured so a fine angular acceleration of the spool we'll give you some of the details on it it's weight is 200 pounds it's radius of gyration it's 2 feet it's actual radius is 3 feet so it's a little more mass towards the rim than it does towards the axle so the radius of gyration is more towards the rim than the axle all right now oh there is another part we need the coefficients of friction between the spool and the truck bed and the level must be some grease on that truck bed I'll have to have it clean and that weight is weight of the spool a free body diagram of the spool free body diagram of the of the spool of roll of paper or burrito obviously it's got a normal force to accelerate right through the truck bed friction in what direction where you can sit out there do you remember the question at the base of the spool as the truck accelerates or I guess the possibility is zero there is no friction couldn't possibly be because in the extremes it sits right there and the truck accelerates away then it's dragging across the bed of the truck there's got to be friction also as it accelerates it accelerates with the truck in that case they're going to have to be friction because otherwise the truck wouldn't be dragging it along so somehow there's friction either way can't be no friction what do we think then to the right or the left right Jake doesn't know Jake wants a new force vector for our classes like that sorry Jake not going to happen Colin you voting yet Bobby you said right Pat you changed to right why do you think it's right now roll to the left now what you have to think is not what the spool is going to do because that's not maybe as obvious as we just saw what you have to think about is what's causing that it's the truck trying to go to the right it's going to have to drag the surface in contact with in the same direction as it so that's the friction force because that's the way the truck bed is going to move it's going to drag that with it now what happens from there isn't as clear if there's no slip then it'll pull the the spool along in that direction it'll start to turn in this direction which means it'll roll a little farther back on the truck which kind of makes sense that's why they tie these loads down at least part of it I assume there's other reasons if it does slip where the truck pulls away so quickly there's actually some slipping there's still going to be this little bit of friction it'll still tend to roll backwards there's our kinetic part for the rotation I think is everybody comfortable that it's going to do that how about though for MAG where's the center of gravity going to go what you have to imagine is you're standing way out here on the side of the road and you're looking and you're seeing this kind of thing happen see the truck pulled away you start to see the spool roll off the truck however if you're looking just at the spool itself not looking at the spool and the truck bed if you're looking just at the spool itself will the spool a little bit later be here in the same place or here no matter where the truck is we have these possibilities here's where it starts a second later the truck has accelerated to there let's draw it a little longer so we can get it on there there's three possibilities that the spool will have gone forward itself a little the spool will have stayed where it was anyway or the spool will actually go backwards some nope it's all there on the board remember looking for where do I put the arrow head on the MAG vector that vector is the sum of the forces there's the only force in that direction so it must be in this direction so this is a case where the spool is going to move forward but it's going to roll backwards because of the motion of the truck bed itself relative to the truck if you were sitting on the truck if you were sitting right there you would see the spool start to roll off the back of the truck but as we look at it out here we're going to see that the spool go forward even though it's rotational motion will be backwards because the object it's on is also moving forward so you have to trust the diagrams there's only one force going in the horizontal direction that's got to be the resultant acceleration of the center gravity so then the equations of motion as a starter two things we just mentioned by the way of course the center of gravity right in the middle there we do have forces in the y direction however there will be no acceleration in all that direction so all that tells us is n is w in this case so we can put those together to say u, w is that fair? because we don't know if it's going to slip at this point or not if the truck goes fast enough it will actually skid backwards relative to the truck bed a little bit if this truck doesn't go too fast then this will be a static friction situation so which is it because now we've got the coefficient of friction in there and we have two choices what we can do assume one or the other then we can solve for this the forces involved and see if our assumption was right that's especially easy with the static one because remember the static coefficient the static friction is quite variable it goes from a minimum of 0 up to a maximum oh sorry Jake don't stop me ever as a fellow alright let's back to tape up a little bit did you think I was talking to you let's assume no slip we've worked with that most often anyway it gives us an extra kinetic equation therefore the maximum possible friction is if we're right at the limit and we got all that stuff maximum possible static friction is 30 pounds if we solve this problem and let's see we've got what three unknowns F alpha and AG but we've got that kinematics kinematics equation for alpha and AG if we assume no slip so we can solve for F check it if it's less than the 30 pounds then this assumption is good if it's greater than the 30 pounds then the assumption that there's no slip won't apply and we'll have to read you the problem then alright then we also need to sum the moments we can do it about G we can do it about the contact point either one's going to work it's your choice about G it's a little bit about the contact point do tend to prefer that how many D stuff tends to be a little bit tricky at times how would you sum it about the other points the contact point you've got all three forces go through there I'm saying I saw a little one right there in fact I hadn't thought of that before well let's finish this and then then we'll talk about it alright we sum the forces about G the only one we have is friction pick a positive direction and we don't have to it only does one thing what F times R go right through there radius of gyration another small problem though here bed itself has its own acceleration the acceleration of the center of gravity is going to be the acceleration G relative to T that's the business we've got that's the no slope condition we can apply there and in this case we know that these are going to be opposite so we're going to need a minus R alpha there because this forward acceleration match the backward with everything we have here we can solve for this force of friction we've got alpha is unknown we've got that to link alpha and AG because AT is known we can solve for the force if that force of friction is less than this 30 pounds then our assumption was good because we have up to 30 pounds of static friction available so over that it breaks loose and starts to slip we've got enough here to solve for we can take AG and eliminate we're now assuming static friction that eliminates AG wait now I'm just going to start we don't want that that's at the static limit we want we want to leave it like that put that into there 0.15 the static coefficient of friction you don't want to assume we're at the static limit because we don't know that we are we just want to know if we're under the static limit okay but then there's no assumption well this is the assumption no slip here but there's no way to check it we can put that in there that single equation for alpha now when you get alpha you can put it in here and see what f is and see if it's greater than the 30 we can assume no slip we can't assume that we're at the static limit alright so you can double check this everything here is known except alpha you can solve for it 1.15 and then Friday we'll double check whether or not our no slip condition is okay what is what? this? no on the left side same equation double I put AG into here for f and then I put f into here so this is f times r f times r the right side of the equation is the same unchanged because that eliminated f from the equation to give me alpha I'm just unsure where this equation came from because normally I think a friction is mu times the normal force at the limit yes we're not at the static limit that's what this is here's the static limit we're assuming that we're not slipping but we're not assuming we're at the static limit remember the coefficient maybe the friction goes up to that point anywhere below that is static friction is a no slip condition if we exceed that which we now know it would be 30 pounds then things start to slip so you can't assume we're right there you can assume we're somewhere in here which is what we assume with this this is the no slip condition otherwise that wouldn't have been true how do you know you're not at that I don't know I'm not that's what I'm going to check if I solve for f and I get 30 pounds I'm right at the static limit and I know if I do one tiny little bit more of acceleration they'll be slippage I said I could assume it's anywhere in here I can't specifically assume one place or the other


I'm one of those lucky people they have two lots that are adjacent to each other. I did a rough count from looking at the NPO overlay and based on the rough sizing on here there is approximately 30 to 32 lots that are 100 by 150 roughly 15,000 square feet. Thank you. Commissioner Bryan any additional questions or comments? No that was it. Great thank you sir. We've had the question answered so we're going to continue. One that's twice the size and it's more than 12,000 square feet. Great thank you. Commissioner Satterfield? No. Commissioner Hornbuckle? I just have a few comments. It this is always it's a can something here it's the it's a difficult decision for us to make but more I just hate to see how it divides the neighborhood and I can see that this has happened here but then again I look I had a lot of memories of Western my grandmother lived on Inglewood my uncle was an old Durham policeman that lived on Alexander Avenue used to coach ball down there at Monkey Bottom play many games down there but I'm in total agreement that with the gentleman you know that I think some of this needs to be addressed as city council and county commissioners the tax rates are ridiculous and I'd be a bit upset too if I had property there in Western and I wanted to sell it or you know take some of these houses down and replace it with something a little larger and just more restrictions on it I think there's enough in place as it is now that there doesn't need to be any more existing ordinances put in place with more restrictions so I'm totally gonna be in opposition to this thank you. Thank you Commissioner. Commissioner Gibbs? And thank you Commissioner Hornbuckle. I won't belabor the issue but that's where I come down. I would like to leave you folks with this thought you are neighbors. I'm not one that's going to be swayed by what percentage is for what percentage is against unless you can have a voting booth set up that doesn't matter to me because there is no way other than a process like that that this a bottom line can be reached but even at that I think the existing zoning works well I took it upon myself twice to ride around the neighborhood and I I don't know who the owners were I didn't want to know who the owners were I just wanted to get a feel for the neighborhood I didn't come across anything that was overbearing there is a big difference in the West the West end of gosh I can't even think the name of the street now but it's where the small lots are when you come back up toward Ninth Street the lots get and the houses get a little bigger but nothing was overbearing there were it mixed in well with some of the existing big houses so I I'm gonna support the existing zoning and you should there are other ways to preserve the history of this area and I encourage you to do those those things to do it you don't need a directive from from the city the county or whatever just amongst yourselves and and other supporters maybe you could buddy with the Watson and Dell people anyway that's all thanks thank you Commissioner Commissioner Williams yeah I have several comments about this particular issue as it relates to the concern of affordable housing and as we talk about affordable housing we talk about density currently it costs us $150 per square foot to build a 2000 square foot home that's 285 thousand two hundred and seventy nine dollars for one home the average existing home there is about 1300 square feet one store brick built which means you have to compromise on a few things excuse me I'm very passionate about this because eventually I will be losing my home for a future laying use map so I have concerns that this issue has been made about affordable housing and it's not this is a control issue this is about who wants to control what when and how I respect the right of those that pay taxes that want to do what they want to with their land but I also respect the right of neighbors they don't want to have accessory dwelling units where they can't enjoy their backyards because people live above them now and can look down they pay property taxes too so I think a compromise has to be had and unfortunately this very strong issue is before the city government because you guys could not compromise and I feel like right now I'm against overbearing properties not in its entirety of the MPO as is written I do believe it needs to be revisited greatly I think that as we talk about trees and tree preservation it was addressed in terms of not necessarily just planting a planting a tree but trees were concerned with overpaving of backyards to make room for 1500 square foot properties as it relates to a parking garage and overhead unit at 1500 square feet that's 150 thousand dollars for that particular unit 3500 dollars per year which would make the rent 291 dollars and 66 cents a month how many people in here actually think that you're going to charge that for that particular property I would think it would be upwards of four times that so let's not talk about affordable housing and density let's just make this about how we can coexist in Durham which is my city born and raised let's figure out how to get this done in the best interest of everyone here that is my comment thank you any additional comments commissioner satterfield thank you mr. chair I just wanted to point out that the MPO is an important tool I think it exists for a reason and despite some of the concerns reservations I respect everybody who's spoken here tonight to express those I think what we're looking at here is a neighborhood that feels like it's under siege and increasingly under siege and I think it's important for the stability of Old West Durham and for the strength of the community even though there's conflict today I'm hoping that that's not always going to be the case that they need some tool like this that they can put in place to make sure that Old West Durham remains the unique community that it is now and for generations to come so I'm gonna be in favor of this thank you any additional comments from any of the commissioners Commissioner Brian I would like to go ahead and make a motion and we move a case yes that we move case number TC 1 8 0 0 0 0 1 Old West Durham and PO or with a favorable recommendation second the motion but as it's presently written I think it needs more work so if we're going to move it as it's presently written I'll be voting against it I would prefer if we can find a way to either defer it or even send it back to let them work on it some more I don't know if that's possible and staff would like to comment on that that's fine right because I'm willing to withdraw the motion provided you know there's an opportunity to do some additional work because it definitely needs some additional work but let's hear from staff because Commissioner Brian I'm not even sure you actually seconded that motion I did second it and I will draw my second okay thank you mr. Brian because this is a text amendment and his owning change the UDO requires that you either vote on it or continue the item within 90 days we would strongly recommend that you vote on it tonight it has been communicated to us by the Old West Durham Neighborhood Association Board and they are welcome to correct me if I'm wrong that they feel that they are kind of at the best compromise they can reach at this point and there's not much more that they can do is that a fair assessment from someone from the board but at this point then Commissioner Brian sorry it's been a long it's been a long evening yes we now want to get a response from the Association or I believe at this point we've we've been here and it is it is time for us to make our recommendation Commissioner Highman Commissioner Busby I'd like to make a motion that we move case number z1800002 the text amendment first yes we have to do both we have to do the text amendment first okay text amendment first yes case number TC1800001 Old West Durham NPO forward with a favorable recommendation second properly moved and second in we will have a roll call vote Commissioner Alturk yes Mr. Brian no Mr. Satterfield yes Commissioner Harris no Commissioner Highman no Chair Busby yes Commissioner Hornbuckle no Commissioner Gibbs no and Commissioner Williams yes motion fails five to four and we will still have a motion on the zoning map change Chair Busby I'd like to make a motion that we move item z1800002 Old West Durham NPO forward with a favorable recommendation second properly moved and seconded we will have a roll call vote as well I just wanted to correct for the record motion passes four to five so it was and and for clarity and the staff make sure I have this right and then we will vote on the zoning motion this motion will be sent forward to the City Council with a four to five vote against so we are the the the recommendation is to deny and when this comes to the City Council it still moves forward regardless we're an advisory body only and we'll have the opportunity to make comments for the City Council just like all of you and I encourage all of you to stay very active and engaged on this issue as I know you will is that accurate staff great thank you so we have a second motion on the zoning case it was properly moved and seconded and we'll have a roll call vote please Mr. Alter yes Mr. Brian no Mr. Satterfield yes Mr. Harris no commissioner Hyman no mr. Busby yes commissioner Hornbuckle no commissioner Gibbs no and commissioner Williams motion fails four to five thank you all very much we appreciate your time and for staying this late a commissioners we are almost finished we don't have any unfinished business and I don't believe there's any new business but I do want to give the staff an opportunity to speak a commissioner Brian we might want to wait just a second or two to let people leave so we can be heard yes that's fair and if folks can head outside and we actually have to still finish business this evening so if you can head out and you can speak out in the lobby that would be appreciated they said it passed for fun I used your mind because of these are going this way and I understood why is this one red yes now it's green I don't know what affects it doesn't affect it and I'll recognize commissioner Brian again if folks can head out into the lobby please we'd appreciate it I would like to make a comment about the MPO and the Planning Commission when Tuscaloosa Lake Park was due to come through the Planning Commission did receive a briefing some months before it came to us that helped us get familiar not only with what an MPO was but with what was going on with Tuscaloosa Lake Park what some of the issues were and I thought that was very helpful I know I've visited out there several times and spent time talking to people whether I had any impact on what they came out with I doubt but still I think that had we been briefed on Old West Durham sometime in advance we may have been able to interact more with the neighbors and maybe giving them some advice and we may have seen something different end of comment thank you commissioner Brian if again if folks could head into the lobby please we're still conducting public business and we can't hear each other thank you while they're making noise could I make a comment you may Commissioner get to what he was just talking about can you get yeah get up to the microphone can you hear me now is there I wish I'm just gonna make a statement I wish we had a copy of your statement yeah him had that was more beneficial to get a good overview of the pluses minuses and all of the codes and all of that in this particular item then all the stacks of paper and emails that we got we tried as staff to put together a thoughtful although long staff memorandum that you know tried to address the pros and cons and give you a clean tick tock so you're able to make sense of some of the correspondence that you received I'd like to have had time to think about it ahead of time but at any rate I don't think the outcome would have been any different but it sure would have saved a lot of guess work and but anyway thank you so much for that and to all the staff my pleasure absolutely any other business for this evening or any other staff reports great I'm gonna thank you all for your time this meeting is adjourned


has anyone ever found genetic data implying a Jewish or Semitic ancestry for any tribe of Native Americans ever? I can't point you to any specific studies at this time. There's no genetic evidence that you know of that supports that. Can you make that admission? No, because I've heard of it. And so, but I can't point you to any specific studies. So you're contradicting the answer you just gave. So you've heard that there is that evidence? There is evidence. I've heard of evidence, but I haven't really gone out and researched it for myself. Well, I think it's time to go out and research that.


What's up everyone it's your girl Kenzie here from Layton Sports Cards and I am ripping a couple of Personals here for Brandon. Oh, we've got a 2022 tops tier one baseball hobby a 2022 tops clearly authentic baseball hobby and a 2021 Panini playbook football hobby. All right Brandon best of luck. Here we go. We're gonna start with some baseball. I'm gonna start with the clearly here. Clearly authentic. It's been pretty hot tonight. All too nice cars out of here. All right, good luck. We've got a Brandon Lau on the rookie acetate auto for the race. Or I'm sorry, Josh Lau. Josh Lau. One's a Lau, one's a Lau. There you go. Tampa on the acetate auto there. Rookie. Very nice. All right and tier one time. Tier one. We've got out of 249 a David Wright's patch mess. David Wright. Another patch here out of 399 Garrett Colt. The Yankees game used. Silver ink rookie one of 10. Alejo Lopez for the Reds. Nice low numbered rookie ink there for you Brandon. One of 10. Alejo Lopez. And last card out of 175. Tier one talent of Larry Walker to 175. Rocky 74 out of 175. Nice big out of there too. All right solid hits for baseball. Let's get into some football. Let's see a big, big booklet here for you. Playbook time. We've got hot routes 25 of 49 three colored patch. DJ Moore. Two boxes. One on one sketch and a comic strip cut auto by the artist. Two boxes. Just insane odd. What's up Bradley? Wow. What's up Kenzie? Out of 99 patch. Cowboys. Amari Cooper. Did you watch your box back? I did. You like your heads? We've got Rams to 75 rookie auto Jacob Harris. Six out of 49. We've got nice Kyle Pitts on the booklet auto. Three colored patch auto. There you go Brandon. Very nice. Congrats on those three boxes. Thanks again for hopping in and we will get these right out to you.


Hey, I'm Andrew Connell. What you're about to watch is the overview lesson to one of the chapters in my MS-600 exam prep guide course. This course is available for purchase on my site, Voitanos.io. I'll include a link to it in the description below the video. This overview video, which is the first lesson of the chapter that you selected, gives you an idea of what the chapter is going to cover. You can learn more by checking out the description below the video about this chapter. If you've got any questions about the chapter or the course, just drop a comment below the video and I'll be sure to get back to you. So with that, let me get out of the way. Enjoy the overview lesson from this chapter. Hello and welcome back. In this chapter, I'm going to focus on the workload called Extend and Customize SharePoint. And while SharePoint is a huge topic, thankfully the MS-600 exam primarily focuses just on the SharePoint framework, which is the recommended way to customize and extend SharePoint. Now, Microsoft SharePoint is a customizable platform that developers can extend with custom components. And the SharePoint framework is the recommended development model to extend the modern SharePoint experience. This workload accounts for 15 to 20% of the questions in the question pool that could show up when you take the exam. In the first iteration of the MS-600 exam, SharePoint had a much stronger focus than it does today. It originally was responsible for 20 to 25% of the questions on the exam, but in the November 2020 refresh of the exam, Microsoft realigned the waiting to put more emphasis on Microsoft Teams than on SharePoint, hence the reduction of SharePoint question pool down to about 15 to 20%. Now that you know what SharePoint is and how much of the exam the questions are going to account for, devoted to SharePoint, let's look at the depth of knowledge that you're going to need to have in these various areas. Recall Bloom's taxonomy from the overview chapter in the course. Let's use that again to provide some context around what you need to know because it helps to understand how deep you need to know something before you embark studying for that topic. This helps you grasp the level of questions that you'll see on the exam. Now, when you look at the skills checklist that Microsoft provides for the MS-600 exam, you'll notice most of the skills include the following words, describe, identify, create, and implement. These phrases fall across the entire spectrum of the taxonomy and that means for SharePoint, we're going to focus on the entire pyramid of the taxonomy all the way from the lower-order thinking skills like remember and understand all the way up to the higher-order thinking skills like evaluate and create. Now let's take a minute to explore what lessons you're going to find in this chapter so that you know what to expect as you proceed through this SharePoint chapter. In this first lesson on the overview, you've learned what extended SharePoint workload is all about. And on the next slide, I'm going to wrap up this lesson with some additional learning resources. So be sure that you check the notes under the lesson video for a collection of all the external references that I use throughout this chapter. The SharePoint workload is quite large and so many products at Microsoft not only come from the SharePoint but also integrate with it. And it has a long history of various ways to extend this product. It also has the added complication that SharePoint routes come from an on-premise installable product while the focus today is the cloud service SharePoint online. So in addition to all of that, we're also on the fourth customization extensibility model for SharePoint. Sounds like a lot, yeah, it is. But just like the other chapters, you don't need to know everything about this topic in order to pass the exam. So in the next lesson, I'm going to call out specific things that you need to focus on as well as things you can ignore as they aren't relevant to the exam. Then we'll begin with a look at an overview of what the SharePoint framework is. The SharePoint framework is commonly referred to as SPFX. So that's how you're probably going to hear me refer to it most of the time throughout this chapter. This lesson is going to look at some of the more global things that you need to be familiar with when it comes to SPFX. And this includes the tools that developers are going to use and also cover elements of SPFX that are not specific to particular types of components or topics that warrant their own discussion or lesson like deployment or working with additional APIs. And the next lesson, I'll cover web parts and the basic building blocks for creating SPFX-based customizations. And we're also going to look at how developers can add support for users either to edit public properties on the web part using property panes and some alternative usage scenarios for web parts such as implementing single-page applications and tabs in custom Microsoft Teams apps. And then we're going to look at the other popular type of component that you can build with SharePoint framework, extensions. These are also referred to as UI extensions and they enable developers to customize modern SharePoint pages and lists in one component. And this lesson, we'll look at the different types of extensions that you could be tested on in the MS-600 exam. Now, after covering the different components that you can create with SPFX, I'll then cover how to consume different types of APIs that are external to the SharePoint framework. And then finally, I'm going to cover the aspects of packaging and deploying SPFX solutions into your production environments. Now, just like all the other chapters in this course, I'm keeping the depth of explanation to the level of what you need to know in order to pass the exam. I'm not trying to go too deep with my explanations because this is an exam prep course. It's not intended to teach you everything about these different topics. But there are plenty of resources that are available to you that you can leverage if you aren't familiar with the topic. So if I cover something in the course that you may think, I got it, I'm comfortable with my knowledge on this topic, then you're probably good. But if you think to yourself, hmm, I don't think I get it. Or if you aren't familiar with the process or a particular API that I cover, then you should go read the official documentation or study one of the multiple resources that I'm referencing throughout the course to make sure that you are adequately familiar with the topic prior to taking the exam. Now I'll reference specific resources throughout the course, but like I said before, be sure to check the notes for this lesson under the video below for a collection of all the external references that I use throughout this chapter. But on this slide, I want to quickly run through the Microsoft Learning resources that I'm providing and explain what's in each one of these. The first group of links is around Microsoft Learning. They have learning paths and modules and a learning path is just a collection of a bunch of modules that have been strung together. The learning path for SharePoint is called Extend Microsoft SharePoint Associate, and it contains the modules used for self-paced study to study for the exam. We then have five modules that cover various topics that I'll reference throughout this chapter and all contain hands-on labs if you want to practice some of the topics you need to be familiar with prior to taking the exam. Now these modules are as follows. Getting started with the SharePoint framework, developing web parts of the SharePoint framework, enable SharePoint framework web property, web part configuration with property panes, work with the SharePoint content using the SharePoint framework, extending the SharePoint framework user interface with SPFX extensions, leverage Microsoft Graph and third-party APIs, deploy SharePoint framework components to production and build teams' customizations using the SharePoint framework. You'll notice a lot more modules in this learning path than others that I've referenced in other chapters throughout the course, and that's because the SharePoint modules were originally written prior to the MS600 exam and the Microsoft Learning content site. So all the modules that support the content covered in the MS600 exam, but they're just broken down into much smaller topics. For example, there are two modules on dealing with web parts, one on web parts and one with web part properties, but in this chapter, I'm covering both of those as a single topic and a lesson rather than breaking it up. SharePoint also contains a ton of documentation as well on their site, and I'll reference a bunch of individual links in the lesson notes, but you can always start at their Docs homepage and, again, found in the notes that accompany this lesson under the video. Okay, before we start looking at specific topics that you're going to be tested on, let's take a step back and let's look at what you need to know and equally as important what you don't need to know in this when you go to take the exam. So let's start with what you really need to know. Now, I know you've heard me say this in every chapter, SharePoint's huge, but seriously, don't worry too much about it in this chapter. Thankfully, you don't need to know everything about extending and customizing SharePoint because when we were developing the certification, we decided to focus on a few different aspects of SharePoint. First, SharePoint is both an on-premise installable server product as well as a hosted cloud service, but remember, this certification is just for Microsoft 365, which is a hosted platform. So while there may be on-premises components or options with MS 365 services, the focus on the certification is the cloud service. So, therefore, the certification only focuses on SharePoint Online, not the installable on-premises version of SharePoint, and that includes SharePoint 2013, SharePoint Server 2016, and SharePoint Server 2019. And also, as I've previously mentioned, SharePoint is a long history of iterating on different development models and extensibility models from full trust solutions to partially trusted solutions known as Sandbox solutions to the add-in model. SharePoint developers have been through quite a lot. The current development model promoted and supported by Microsoft as SharePoint Online, and it's called the SharePoint framework. This model, specifically the SharePoint framework, is the only one that the MS600 exam is going to focus on. So I'm going to go into detail on the depth of knowledge that you should have around SPFX within the lessons throughout this chapter, specifically how well you need to know these different APIs. So let's switch gears. Instead of talking about what you need to know, let's talk about what you can ignore in your preparation for the exam. I think I've already covered this enough, but just to be clear, if it's not SPFX and it's a way to customize SharePoint, you don't need to know it for the exam. This means that you can ignore everything about fully trusted solutions or partially trusted solutions and even add-ins. You don't need to concern yourself with anything other than SPFX for customizing SharePoint when it comes to the MS600. Now, unlike early versions of the MS600 exam, you're not going to be tested on the theming or the branding options that are available in SharePoint. Early on, there weren't many questions in this area, and in that big August 2022 update of the exam, they've fully removed this section from the exam. And in recent years, Microsoft has invested quite a bit in the declarative customization options for SharePoint. You've got things like list formatting, row formatting, column formatting, as well as using things like site designs and site scripts for provisioning assets. These are all capabilities that are supported by SharePoint Online, but none of these technologies are on the MS600 exam. None of them are listed within the skills assessment worksheets, so these are things you do not need to concern yourself with. Another area that Microsoft has invested a lot in with respect to SharePoint is in something called the Power Platform. Two particular aspects of this are Power Apps and Power Automate, we used to call that flow. Power Apps are touted as the way to customize SharePoint forms, and Power Automate is positioned as the workflow solution for SharePoint Online, but neither of these are going to be covered on the MS600 exam. In fact, there is nothing related to the Power Platform that you'll be tested on with the MS600 exam. There are other exams for that actually. Now, the SharePoint framework is a client-side framework that runs in the browser, and this means it's rooted in JavaScript, but developers use TypeScript to write SharePoint framework components. Microsoft offers lots of different APIs and SDKs to connect to SharePoint APIs, including the client object model, also known as the CSOM, and plenty of community projects from the Microsoft 365 Patterns and Practices Group, but none of these will be covered on the exam. Also, just like the other workloads I've covered, only the official APIs provided and supported by Microsoft are covered on the MS600 exam, and those are limited to just SPFX. Furthermore, you don't need to pay any attention to any of the PowerShell Commandlets or community-related projects related to SharePoint. This includes PowerShell Commandlets from Microsoft Proper or from the Microsoft 365 P&P Group. Okay, that wraps up the overview lesson. In the next lesson, we're going to cover an overview of SPFX and what things you need to pay attention to. So I will see you in the next lesson.