# Rotational Motion in Physics: Tutoring Solution Chapter Exam

Choose your answers to the questions and click 'Next' to see the next set of questions. You can skip questions if you would like and come back to them later with the yellow "Go To First Skipped Question" button. When you have completed the practice exam, a green submit button will appear. Click it to see your results. Good luck!

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#### Question 1 1. A spinning top is spun at 720 degrees in five seconds, by applying a torque of 10 newton-meters. How much power is being transferred to the spinning top? Note: 180 degrees is equal to pi (3.14) radians.

#### Question 2 2. How do we know that rotating objects have kinetic energy?

#### Question 3 3. Which of the following is the rotational version of Newton's 2nd Law?

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Question 4
4.
Which of the following is NOT one of the big 5 equations for rotational motion with a constant acceleration?

(Note: In the images below, w0 is the initial angular velocity, and w is the final angular velocity. This is another way of notating the same thing, which you may well see in problems and tests.)

#### Question 5 5. Which of the following is the rotational version of Newton's 1st Law?

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#### Question 6 6. A spinning top is spun at an angular velocity of 3 radians per second, by applying a torque of 10 newton-meters. How much power is being transferred to the spinning top?

#### Question 7 7. Instead of mass (used in translational motion), what do we use in the equation for rotational kinetic energy instead?

#### Question 8 8. If the initial angle of a turntable compared against an arbitrary line is 20 degrees, and half a second later it has rotated to 370 degrees, what is the angular velocity of the turntable?

#### Question 9 9. Which of the following is NOT a rotational kinematics quantity?

#### Question 10 10. A certain disk has a moment of inertia of 1000 kg⋅m2. What torque would be required to get it to spin from rest to 10 revolutions-per-second in 0.5 sec?

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#### Question 11 11. A spinning top has a moment of inertia of 2 kilogram meters squared. How much torque does it take to accelerate it at a rate of 10 radians per second per second?

#### Question 12 12. Which of the following defines inertia?

#### Question 13 13. A spinning top with uniform mass distribution is rotating around its axis at a rate of three rotations every six seconds. If the moment of inertia of the object is 2 kg m^2, how much rotational kinetic energy does the spinning top contain?

#### Question 14 14. Which of the following is a correct definition of moment of inertia?

#### Question 15 15. Which of the following is a correct definition of torque?

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#### Question 16 16. When an object is in rotational equilibrium the sum of which external property acting on the object must equal zero?

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Question 17
17.
A rubber ball (*m* = 1 kg, *r* = 0.5 m)) moving at 10 m/s strikes a metal rod (*m* = 2 kg and length of 1 m) hanging from a pin at its geometric center. After the collision, the rubber ball falls straight to the ground and the rod moves with an initial angular speed of 2 rad/s. At what angle did the rubber ball strike the metal rod? *I*rod about its center = (1/12)mL2.

#### Question 18 18. Which of the following is a correct definition of moment of inertia?

#### Question 19 19. Which of the following is an example of an object experiencing rotational motion?

#### Question 20 20. A planet is orbiting a star in a wildly elliptical orbit. The planet has a mass of 3 x 10^4 kilograms, a velocity of 3 x 10^3 meters per second, a radius of 7 x 10^13 meters, and is orbiting at an angle of 70 degrees to the star. When the planet reaches its closest point of approach, at a radius of 2 x 10^12 meters, and an angle of 90 degrees, approximately how fast will it be moving?

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#### Question 21 21. What is true about the velocity an object can experience while under translational equilibrium, and the angular velocity an object can experience while under rotational equilibrium?

#### Question 22 22. Which of the following is NOT an example of torque in the real-world?

#### Question 23 23. If you hold a stack of heavy books for 10 minutes, are you doing work, and why?

#### Question 24 24. Which of the following quantities does not affect an object's angular momentum?

#### Question 25 25. Which of the following people has the most linear momentum?

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#### Question 26 26. Why are light bulbs measured in watts (power) instead of joules (work)?

#### Question 27 27. Imagine a ball rolling down a hill without friction. To measure the moment of inertia, which of the following is NOT a measurement you would need to take (or figure out)?

#### Question 28 28. What is the angular variable that corresponds to the linear variable 'time'?

#### Question 29 29. A spinning top increases the rate at which it spins from 5 radians per second, at an angular acceleration of 3 radians per second per second. If it continues to accelerate for 4 seconds, what will the final angular velocity be?

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Question 30
30.
Use the following data from a repeat of the ball experiment, to figure out the moment of inertia of a second ball:

Mass of the ball: 1 kg.

Radius of the ball: 0.02 meters.

Height of the hill: 0.3 meters.

Translational velocity at bottom: 2.2 m/s

Rotational velocity at bottom: 80 rads/s

#### Rotational Motion in Physics: Tutoring Solution Chapter Exam Instructions

Choose your answers to the questions and click 'Next' to see the next set of questions. You can skip questions if you would like and come back to them later with the yellow "Go To First Skipped Question" button. When you have completed the practice exam, a green submit button will appear. Click it to see your results. Good luck!