Unit 5: Rotation

An ice skater spinning with arms extended pulls her arms in. What happens to her angular velocity?

A wheel completes 10 revolutions in 5 seconds. Its angular velocity is

A disk and a hoop of the same mass and radius roll down a frictionless incline from the same height. Which reaches the bottom first?

A figure skater pulls her arms inward during a spin, reducing her moment of inertia by half. Her angular velocity

The centripetal acceleration of an object moving at 10 m/s in a circle of radius 5 m is

A wheel of radius 0.5 m rotates at 10 rad/s. The linear speed of a point on its rim is

A spinning disk has angular momentum [math]. If its moment of inertia is halved while no external torque acts, its angular velocity becomes

A wheel accelerates uniformly from rest to 120 rad/s in 6 s. The number of revolutions it makes is

Airbags in cars reduce injuries by:

In which type of collision is kinetic energy conserved?

A 2 kg ball moving at 5 m/s collides head-on with a 3 kg ball at rest. They stick together. What is the final velocity?

The total momentum of an isolated system (no external forces):

A 0.2 kg ball moving at 10 m/s to the right bounces off a wall and returns at 8 m/s to the left. What is the magnitude of the change in momentum?

An object at rest explodes into two pieces. What can be said about their momenta?

On a Force vs. Time graph, the impulse on an object is represented by:

A 10 g bullet traveling at 400 m/s embeds in a 2 kg block. What is the velocity of the block-bullet system?

In an elastic collision:

A ball is thrown at a wall. Which scenario results in a greater impulse on the wall — the ball bouncing off or sticking?

If no external forces act on a system, the center of mass:

What is the angular velocity of the wheel?