Conservation of Momentum (Collisions) In A Nutshell

Like conservation of energy problems, every momentum problem is kind of the same: plug the numbers from the problem into the conservation of energy equation and hope you can solve for the thing they're asking for. There are a few tricks, though, so this video gives you "the view from 10,000 feet" of momentum problems, before digging into the nitty gritty in the rest of the momentum videos.

1-D Inelastic Collisions (momentum only)

The most basic conservation of momentum problems are the inelastic ones where the two objects "stick" together or become "entangled" after they collide. After I show you the algebraic trick for these, you'll mock these if you see one on a test.

1-D Elastic Collisions (momentum and energy)

This video covers the famous billiard ball problem which every professor and book uses as an example for elastic collisions in one dimension. Elastic collisions are not your friend, because even though momentum is conserved (easy), you have to also use the conservation of energy (harder, since everything is squared).

2-D Inelastic Collision Problems (momentum only)

Two-dimensional inelastic collisions are a lot like 2-D force problems: everything has to be broken up into X and Y components. On the bright side, it's inelastic, so at least nothing is squared like it is for elastic collisions. The example in this video is the classic "two cars collide at 90° then stick together" problem.

2-D Elastic Collisions (momentum & energy)

Two-dimensional elastic collisions are no picnic, so if you see one of these on a test, I pity you. On the other hand, if the only problem you have trouble with on your energy & momentum exam is this one, you're probably setting the curve in your class anyways, so don't cry too big a river.

Momentum In Explosions (items breaking apart)

Most momentum problems involve two items colliding. This video covers the other type, where two items start together but separate at high speed, so it's kind of like an inelastic collision in reverse. The examples covered include calculating the recoil of a cannon as it fires a bullet, and a figure skater giving his partner a push so she can launch a triple axle.

Rocket Thrust Momentum Problems

Rockets aren't covered by every intro physics class, but to me they are the coolest thing about momentum. I don't know about you, but I love watching SpaceX launches (and landings), it's just freaking unbelievable, and the more you know about the physics underlying those things, the crazier it is that the whole thing is even possible!