Angular Momentum

Overview of Angular Momentum

Angular momentum is pretty straightforward except for one little detail: it's kind of funky that you can calculate the angular momentum of an object that's moving in a straight line. Like you could willy nilly calculate the linear momentum of the next jogger you see run past you. Even crazier, since the jogger ins't rotating, you can pick any axis you want, potentially making their angular momentum HUGE if you pick an axis a block away. This video explains that.

Projectile Sticks to a Door

Every book has some version of this problem: sticky projectile collides with a rod that's hinged at one end and you figure out how fast the rod rotates. What a lovely way to combine linear and rotational motion! Maybe your teacher will put it on your test!

Kids Move From Center of Platform To Edge

In this problem we look at a classic piece of playground equipment which - like so many of the greats - is pretty hard to find these days, probably because it was too dangerous. But they were all over when I was a kid in the Midwest and they were AWESOME! A great way for kids to learn about centripetal forces, dizziness, the gyro effect, and even negotiating with your friends and their parents to see who was going to push.

Angular Momentum and Work

This is a problem you see in lots of physics classes, sometimes involving astronauts or satellites attached by a tether. It turns out that in angular momentum problems, angular momentum is always conserved, but energy isn't. And in a surprise twist, in this problem kinetic energy actually increases! What the what?! That's work, my friend!