A student holds a spinning bicycle wheel while sitting motionless on a stool that is free to rotate about a vertical axis through its center (see the figure below). The wheel spins with an angular speed of 18.6 rad/s and its initial angular momentum is directed up. The wheel's moment of inertia is 0.130 kg. m² and the moment of inertia for the student plus stool is 3.50 kg. m². HINT Lwheel Lwheel (a) Find the student's final angular speed (in rad/s) after he turns the wheel over so that it spins at the same speed but with its angular momentum directed down. rad/s (b) Will the student's final angular momentum be directed up or down? O up O down

A 1.80 m radius playground merry-go-round has a mass of 120 kg and is rotating with an angular velocity of 0.350 rev/s. What is its angular velocity, in rev/s, after a 28.0 kg child gets onto it by grabbing its outer edge? The child is initially at rest.

A playground merry-go-round has a mass of 120 kg and a radius of 1.80 m and it is rotating with an angular velocity of 0.450 rev/s. What is its angular velocity (in rev/s) after a 28.0 kg child gets onto it by grabbing its outer edge? The child is initially at rest. Ex rev/s S Stanned with CamScanner er a unber Additional Materials O Reading

A merry-go-round has a radius of 16.5 m and a moment of inertia of 310 kg-m². A boy of mass 44.9 kg runs tangent to the rim at a speed of 4 m/s and jumps on. If the merry-go-round is initially at rest, what is the angular velocity after the boy jumps on? Help on how to format answers: units w/

Kacey is learning how to figure skate. She is spinning with her arms out, each arm is .5 m, with an angular velocity of 2 rad/s. Her teacher tells her to pull in her arms for a total radius of 0.15 m. What is her angular velocity?

A 0.1 kg solid disc has a radius of 0.2 m. The moment of inertia of a solid disc is I = ½ m r2. EXAM  The disc initially rolls with a velocity of 2 m/s along a horizontal surface. It then rolls up a ramp and briefly stops when it reaches a height h.  The disc rolls without slipping on both surfaces.  a) What is the angular velocity of the disc when it is on the horizontal surface?  b) What is the speed of a point on the very top of the disc when the disc is on the horizontal surface?  c) Use Conservation of Energy to find the maximum height of the disc, h.  d) If the disc were replaced with a thin ring (same mass, same radius, same initial speed), would it roll higher, less high, or the same height? No calculations required. Briefly explain your answer!  e) If there were no friction (the disc slides instead of rolling), but the disc still has the same initial speed, would it roll higher, less high, or the same height?

A 85.0-kg skater begins a spin with an angular speed of 8.00 rad/s. By changing the position of her arms, the skater decreases her moment of inertia to one-fourth its initial value. What is the skater's final angular speed? my final answer is 16 rad/s? I'm not sure if it's correct because on test it was marked as incorrect. Can you please explain why it's incorrect?