Name:    Ch 14 - Vibrations and Waves Test

True/False (Value 5)
Indicate whether the statement is true or false.

1.

A standing wave results from the interference of two waves of equal wavelength that travel in opposite directions.

2.

When work is done on a spring to stretch it, elastic potential energy is stored in the spring.

3.

When a mass suspended from a spring is in its equilibrium position, the upward force exerted by the spring is equal to the downward force exerted by gravity acting on the mass.

4.

The period of a simple harmonic oscillator is the time it takes for one complete cycle of oscillation to be completed.

5.

Destructive interference between two superimposed waves can result in a node, or point with no displacement.

Multiple Choice (Value 5)
Identify the choice that best completes the statement or answers the question.

6.

Tapping the surface of a pan of water generates 17.5 waves per second.  If the wavelength of each wave is 45 cm, what is the speed of the waves?
 a. 7.9 m/s c. 39 m/s b. 790 m/s d. 2.6 m/s

7.

What is the period of a pendulum near Earth’s surface that is 130 cm long?
 a. 2.3 s c. 22.9 s b. 0.83 s d. 9.1 s

8.

If wavelength is kept constant, which increases as the speed of a wave increases?
 a. period c. phase b. amplitude d. frequency

9.

Which is not an example of resonance?
 a. a child swings higher as she is pushed on a swing b. a guitar string is repeatedly plucked c. a car bumper bounces back after a collision d. a basketball is dribbled down the court

10.

In the diagram, the wavelength is shown by:
 a. a c. c b. d d. b

Completion (Value 5)
Complete each statement.

11.

Hooke’s Law states that the force exerted by a spring is ____________________ to the amount that the spring is stretched.

12.

Longitudinal waves vibrate ____________________ to the direction the wave propagates.

13.

The ____________________ of a pendulum depends only on the acceleration due to gravity and the length of the pendulum.

14.

Points on a wave that are an integer number of wavelengths apart from one another are said to be ____________________.

15.

On a graph of force versus displacement of a spring, the ____________________ is given by the slope of the line.

16.

What data are required to experimentally determine the value of k?

17.

Explain the meaning of the negative sign in the equation for Hooke’s Law.

Problem (Value 12)

Displacement of a Spring

18.

How much potential energy is stored in the spring if it is displaced 0.6 m?

19.

The displacement of a spring when different amounts of force are applied is shown in this graph.  What is the spring constant of this spring?

20.

A lifeguard on a beach observes that waves have a speed of 2.60 m/s and a distance of 2.50 m between wave crests. What is the period of the wave motion?

21.

A spring has 54,000 J of elastic potential energy stored when it is stretched out.  If its spring constant is 285 N/m, how much has the spring been stretched?