Rotation Practice Test! 
Answer key! 


1. A disk drive is rotating at 5000 rev/s what is the angular velocity of the disk drive?
2. What is the angular displacement of an merrygoround that has the radius of 5m and is rotating 3 rotations in 5 seconds. What is the angular displacement over the course of 10 minutes?
3. If an fan is rotating at 30π rads/s then what is the angular displacement in 4.23 seconds?
4. A constant torque is applied to the end of a bicycle tire (it has a moment of inertia of 12 kg*m^2) and it is accelerated to 60 rpm in 10 seconds. What is the magnitude of the torque?
5. A figure skater is twirling at 3 rotations per second with a moment of inertia of 20 kg*m^2 at that moment of time. What has to occur if she is to speed up to 10 rotations per second? Assume no new, unbalanced torques were added into the system.
6. A merrygoround constantly accelerates from rest to .5 rads/s in 30 s. Assuming the merrygoround is a uniform disk 6 m and mass 30000 kg, calculate the average net torque required to accelerate it.
7. A wheel 20 cm in diameter accelerates uniformly from 240 rpm to 300 rpm in 5 s. How far will a point on the edge of the wheel have traveled in this interval of time?
8. A centrifuge rotor rotating at 9200 rpm is shut off and is eventually brought uniformly to rest by a frictional torque of 1 mN. If the mass of the rotor is 3.1 kg and it can be approximated as a solid cylinder of radius . 05 m, how many rotation will it take for the rotor to stop?
9. A bowling ball of mass 6 kg and radius 10 cm rolls without slipping down a lane at 3 m/s. Calculate its total kinetic energy?
10. Explain to someone (who isn’t well versed in physics) what is going on when a figure skater speeds up when she bring her hands closer and slower when she brings her hands out.
2. What is the angular displacement of an merrygoround that has the radius of 5m and is rotating 3 rotations in 5 seconds. What is the angular displacement over the course of 10 minutes?
3. If an fan is rotating at 30π rads/s then what is the angular displacement in 4.23 seconds?
4. A constant torque is applied to the end of a bicycle tire (it has a moment of inertia of 12 kg*m^2) and it is accelerated to 60 rpm in 10 seconds. What is the magnitude of the torque?
5. A figure skater is twirling at 3 rotations per second with a moment of inertia of 20 kg*m^2 at that moment of time. What has to occur if she is to speed up to 10 rotations per second? Assume no new, unbalanced torques were added into the system.
6. A merrygoround constantly accelerates from rest to .5 rads/s in 30 s. Assuming the merrygoround is a uniform disk 6 m and mass 30000 kg, calculate the average net torque required to accelerate it.
7. A wheel 20 cm in diameter accelerates uniformly from 240 rpm to 300 rpm in 5 s. How far will a point on the edge of the wheel have traveled in this interval of time?
8. A centrifuge rotor rotating at 9200 rpm is shut off and is eventually brought uniformly to rest by a frictional torque of 1 mN. If the mass of the rotor is 3.1 kg and it can be approximated as a solid cylinder of radius . 05 m, how many rotation will it take for the rotor to stop?
9. A bowling ball of mass 6 kg and radius 10 cm rolls without slipping down a lane at 3 m/s. Calculate its total kinetic energy?
10. Explain to someone (who isn’t well versed in physics) what is going on when a figure skater speeds up when she bring her hands closer and slower when she brings her hands out.