Practice Quiz SHM (CHAPTER 14)

1) The position of a mass that is oscillating on a spring is given by x = (12.3 cm) cos[(1.26 s-1

)t]. What is the

acceleration of the mass when t = 0.825 s?

A) 9.89 cm/s2

B) -9.89 cm/s2

C) 10.6 cm/s2

D) -10.6 cm/s2

Answer: B

2) A sewing machine needle moves up and down in simple harmonic motion with an amplitude of 1.27 cm and a

frequency of 2.55 Hz. What is the maximum acceleration of the needle?

A) 8.26 cm/s2

B) 16.5 cm/s2

C) 326 cm/s2

D) 163 cm/s2

Answer: C

3) When a mass of 0.350 kg is attached to a vertical spring and lowered slowly, the spring stretches a distance d.

The mass is now displaced from its equilibrium position and undergoes 100 oscillations in 48.9 s. What is the stretch

distance d?

A) 2.35 cm

B) 4.71 cm

C) 5.94 cm

D) 6.28 cm

Answer: C

4) A mass of 0.150 kg is attached to a spring with a force constant of 3.58 N/m and undergoes simple harmonic

oscillations with an amplitude of 7.50 cm. What is the total mechanical energy of the system?

A) 0.0201 J

B) 0.0101 J

C) 0.269 J

D) 0.134 J

Answer: B

3) An astronaut has landed on an asteroid and conducts an experiment to determine the acceleration of gravity on

that asteroid. She uses a pendulum that has a period of oscillation of 2.00 s on Earth and finds that on the asteroid

the period is 11.3 s. What is the acceleration of gravity on that asteroid?

A) 0.307 m/s2

B) 1.74 m/s2

C) 5.51 m/s2

D) 0.0544 m/s2

Answer: A

6) A pendulum that was originally erected by Foucault at the Pantheon in Paris for the Paris Exhibition in 1851 was

restored in 1995. It has a 28.0 kg sphere suspended from a 67.0-m light cable. How long would it take for the bob in

this pendulum to move from the position of maximum displacement back to the equilibrium point?

A) 4.11 s

B) 21.5 s

C) 32.2 s

D) 42.9 s

Answer: A

7) A child and an adult are walking. Their legs swing like physical pendulums and both swing through the same

maximum angle. The adult is 1.5 times as tall as the child, and all their dimensions are scaled proportionately. They

also have the same mass per unit volume. If the walking speed of the adult is 1.3 m/s, what is the walking speed of

the child? (see the example 14.9 on physical pendulum on p 456)

A) 4.85 m/s

B) 2.86 m/s

C) 1.1 m/s

D) 2.39 m/s

Answer: C

8) A light rod of length L is pivoted at the center and can rotate in a vertical plane. At the lower end of the rod there

is a mass M and at the upper end there is a mass M/2. If it is given a small displacement from equilibrium, what is

the angular frequency of the resulting oscillations?

A) (2g/L)1/2

B) (g/2L)1/2

C) (2g/3L)1/2

D) (3g/2L)1/2

Answer: C

9) A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of

the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant

acceleration?

A) The period does not change.

B) The period increases.

C) The period decreases.

D) The period increases if the upward acceleration is more than g/2 but decreases if the upward acceleration is less

than g/2.

Answer: C

10) A mass of 1.53 kg is attached to a spring and the system is undergoing simple harmonic oscillations with a

frequency of 1.95 Hz and an amplitude of 7.50 cm. What is the total mechanical energy of the system?

A) 0.844 J

B) 0.646 J

C) 0.633 J

D) 0.955 J

Answer: B