A 40 kg child sits 1.5 meters away from the center of a teeter-totter. How much force does his dad need to exert 2 meters from the center (on the other side) to prevent the child from moving?
Angular Momentum = rotational inertia x angular speed
15.
Conservation of Angular Momentum Why do ice skaters spin so much faster when they bring their arms close to their bodies?
16.
Conservation of Angular Momentum To understand why ice skaters, divers, & gymnasts spin faster when they bring their bodies in we must discuss the Conservation of Angular Momentum.
If no external torque acts on a rotating system, the angular momentum of that system is constant.
Angular Momentum Before = Angular Momentum After Rot. Inertia x Rot. Velocity = Rot. Inertia x Rot. Velocity (before) (after)
18.
The Angular Momentum for both is the same because they have to be the sameā¦ITāS A LAW! big rotational inertia small rotational inertia small rotational velocity big rotational velocity
Angular Momentum like linear momentum is a vector. Direction is important!
20.
The Direction of Angular Momentum Because the direction of something rotating is hard to determine, physicists say that the direction of angular momentum is in the plane of the rotation. If this wheel was rotating, we would say its angular momentum is pointed in this direction. So it would want to stay rotating in that direction.
21.
Examples of Angular Momentum So next time you play: Remember you are just conserving angular momentum. - Football - Frisbee - Ride your bike
Be the first to comment