Study Guide for Examination #3
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A torque of 42 Nm gives a large wheel an angular acceleration of 0.78 rad/s2. What is the moment of inertia of the wheel?
a. 12 kgm2 b. 32 kgm2 c. 54 kgm2 d. 108 kgm2
2. A phonograph turntable rotating at 33.3 rev/min is turned off and coasts to a stop after completing 5 rev. What was its angular acceleration?
a. -0.19 rad/s2 b. –0.83 rad/s2 c. –1.1 rad/s2 d. –2.1 rad/s2
3. A turntable rotates through 10 radians in 4 seconds. The turntable experiences uniform acceleration. If the turntable
started from rest, what is its angular velocity at the end of the 4 seconds?
4. An ice skater is in a fast spin with her arms held tightly to her body. When she exerts her arms, which of the following statements is not true?
a. She increases her moment of inertia b. She decreases her angular speed c. Her moment of inertia remains constant
d. Her total angular momentum remains constant
5. A circular ring has a mass of 12 kg and a diameter of 144 cm. It is rotating about its center at an initial angular velocity of 600 rev/min. If dropped at the bottom of a frictionless plane that is
inclined 30¥ above the horizontal, how far will it roll up the incline?
7. A grinding wheel, mass 200 kg and moment of inertia of 550 kgm2, starts from rest and develops a constant torque of 1200 Nm.
A. What is the angular acceleration of the wheel? B. What is its angular velocity after 5 revolutions?
C. How much work was done by the motor during the first 5 revolutions?
8. A horizontal plank 8 m long has a mass of 25 kg. A person of mass 63 kg stands on one end of the plank while a
second person of mass 105 kg stands on the other. Where should the fulcrum be placed in order that the plank be in equilibrium?
9. The maximum value for the displacement of a harmonic oscillator is called the
a. frequency b. period c. wavelength d. amplitude
10. If the amplitude of a simple harmonic oscillator is doubled, the total energy is
a. doubled b. halved c. quadrupled d. unaffected
11. A 330 g mass attached to one end of a spring is executing simple harmonic motion. The amplitude of the motion
is 14 cm and its velocity is 3.7 m/s as it passes through the equilibrium position. What is the spring constant for the spring?
12. The period of a simple pendulum is determined to be 1.5 seconds on Earth. What would it be on the moon where the acceleration of gravity is approximately 1/6 of Earth's gravity?
13. A block of mass 4.5 kg on a horizontal frictionless surface is attached to a horizontal spring. The block is set into
simple harmonic motion with amplitude 14 cm and period 2 seconds.
A. What is the maximum force the spring exerts on the block during its motion? Where does the maximum force occur? B. What is the force on the block after 2.75 seconds? Assume no damping.
14. The wave shown in the fig. is being sent out by a 60 Hz vibrator. What is the amplitude, period, and frequency of the wave?
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