Rotation Review & Intro to Angular Momentum

In the picture, what force creates torque on this system?

• gravity

• tension

• normal

• friction

In this picture, which radius should be used to find the torque?

• the blue cylinder's radius

• the black pulley's radius

• the grey disk's radius

• the light grey base's radius

A mass falls while attached to a hoop that is free to rotate. The mass accelerates at a rate

• less than 9.8 m/s²

• equal to 9.8 m/s²

• greater than 9.8 m/s²

A mass falls to the floor while attached to a hoop that is free to rotate. Which force is larger?

• gravity > tension

• gravity = tension

• gravity < tension

A star collapses such that it retains the same mass but becomes much denser. Which of the following quantities changes as a result?

• rotational speed decreases

• linear speed decreases

• rotational inertia decreases

• kinetic energy decreases

What force provides the torque that causes the Earth to rotate on its axis?

• gravity

• chemical bonds

• normal force

• no force needed to rotate

A rock rolls down a hill with friction such that it reaches a speed v at the bottom. It then rolls down a frictionless hill and its speed at the bottom is...

• less than v

• equal to v

• greater than v

A hoop, cylinder, and solid sphere roll down a hill such that that roll without slipping. Which reaches the bottom of the hill first?

• hoop

• cylinder

• solid sphere

• all the same

If the hill were frictionless, which would reach the ground first?

• hoop

• cylinder

• solid sphere

• all the same

What is the torque in these scenarios?

• Fg*r

• Fn*r

• Ff*r

• 2Fg*r