Unit: Rotation I.Coordinates:  = s/R,  = v t /R,  = a t /R II.Kinematics: same form, new variables III.Energy: A.Moment of Inertia (rotational mass): I =  mr 2 B.Rotational Kinetic Energy: K = (1/2)I  2 C.Rolling Bodies: only the type of shape matters IV.Torque (rotational force):  = rFsin  V.Angular Momentum: A.L = rpsin  = I  B.  t =  L C.Conservation today

A ball rotates around on a string. If the string length were doubled and the velocity held constant, what would happen to the angular momentum?

A solid disk and a hoop of equal radius both rotate around at the same frequency. If they weigh the same amount, which has the greater angular momentum? a) the disk b) the hoop c) they have the same angular momentum

A merry-go-round rotates counterclockwise (from above). Which way does the angular momentum vector point?

A 10kg merry-go-round rotates counterclockwise (from above). A child leans up against the outside edge (2m from the middle), providing a constant frictional force. Which direction does the torque vector point?

A 10kg merry-go-round rotates counterclockwise (from above). A child leans up against the outside edge (2m from the middle), providing a constant frictional force of 30N. At what rate does the angular momentum decrease?

You are riding your bicycle through campus. Which way does the angular momentum vector of your tires point?

A 5,000kg plane is flying 200m/s at a constant altitude of 8,000m. What is the angular momentum of the plane about you when you see the plane from the quad at Houghton College.

The system below is released from rest. What is the direction of the net torque on the pulley? 20kg 10kg

You are riding your bicycle down Rt. 19. You suddenly jerk your handle bar to the left. What does this cause the tire to do?