Projectile Motion

Projectile Range Across Flat Field (no elevation change)

Projectile problems are all kind of the same, except for subtleties like whether the projectile lands at the same altitude it was launched from. This video starts off with the range equation, which is an easy-to-use formula that only works for the same-altitude situation. Because the range formula is so limited, though, the video also shows you how to do those problems with the kinematics equations, which you'll have to know cold for other types of problems.

Projectile Range with Elevation Change

This video explains the ins and outs of kinematics problems where the projectile lands at a higher or lower level than it was launched from. Why is that such a big deal? SPOILER ALERT: because the Yo and Yf are different, you'll need the quadratic formula! That may seem crazy at first, but once you've watched a few of these videos, you'll be chuckling confidently at whatever your prof tries to throw at you on the exam.

Projectile Max Height

This video covers a problem type that is often one of the parts of those full-page, multi-stage problems that physics profs love to put on exams. Somewhere in the midst of asking you about an arrow being shot up a hillside, they'll squeeze in a question about how high the arrow is at the peak of its arc.

Projectile Launched Horizontally from High Place

Yet another video about a specific type of kinematics projectile problem. This one covers projectiles which are launched sideways, usually off a high place, because that means that the vertical component of initial velocity is zero. Exciting, right?! Kind of, actually, because it makes it a bit simpler to solve for t, if that's something you're into.

Projectile Dropped From An Airplane

Similar to the previous video, this one also covers a problem type where the initial velocity is horizontal. So why make it a separate video? Because every physics class seems to cover these, and every physics student is a bit confused by them. Gee, I wonder if the teachers like these BECAUSE they know students are confused by them...

Will This Projectile Clear The Obstacle?

The problems in this video are things like: If a football is kicked at a certain speed and angle from 65 meters away, will the ball clear the horizontal bar that's 3m off the ground? The basic idea is that instead of asking you how far a projectile will go, they give you a distance and ask if the projectile will be high enough to clear it. Another popular topic for this type of problem: whether a baseball will be a home run.

Projectile Aimed At A Target

This video covers a problem where a gun or arrow is aimed at a target, but gravity causes the projectile to miss low. The second, trickier half of the problem is when they ask you what angle to correct the aim by to compensate for gravity. Sounds reasonable, but it seems like it requires a few little tricks that most students aren't aware of, so I do my best to explain how I'd approach this one.

That Problem Where Something Falls From Tree At Same Time Gun Fired

This video covers a problem that's very common in physics lectures: your prof might do it as an in-class demo, or if you're really lucky you might get to do it in lab! A dart is fired at the same time the target is dropped, yet the dart magically hits the target on the way to the floor. Awesome.

Ski Jump Problems

You may not have noticed, but all the projectile problems up to now have dealt with level surfaces: whether the object was being dropped from an airplane or shot from a cannon, it always seems to be landing on a level surface. This video tells you what to do with a ski jump or other situation where the landing surface is a slope or other shape that can be defined by a function of X and Y.

Quadratic Formula on Calculator

This is a quick tutorial on how to do the quadratic formula on your calculator if you don't have one of those programs that does it for you. The main thing is being organized with your parentheses, and there's also that great 2nd-Enter trick so that you don't have to re-type everything for the second part of the "plus or minus" at the center of the quadratic formula.