Chapter 19: Vibrations and Waves

Question 1

The waveform traced by simple harmonic motion, which can be made visible on a moving conveyor belt by a pendulum swinging at right angles above the moving belt.

Answer 1

Sine curve

Question 2

For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position.

Answer 2

Amplitude

Question 3

The distance between successive crests, troughs, or identical parts of a wave.

Answer 3

Wavelength

Question 4

For a vibrating body or medium, the number of vibrations per unit time. For a wave, the number of crests that pass a particular point per unit time.

Answer 4

Frequency

Question 5

The SI unit of frequency.

Answer 5

Hertz; 
One hertz (symbol Hz) equals one vibration per second.

Question 6

The time in which a vibration is completed.

Answer 6

Period;

The period of a wave equals the period of the source and is equal to 1/frequency.

Question 7

The speed with which waves pass a particular point.

Answer 7

Wave speed;

wave speed = frequency x wavelength

Question 8

A wave in which the medium vibrates in a direction perpendicular to the direction in which the wave travels.

Answer 8

Transverse wave;

Light waves and water waves are transverse.

Question 9

A wave in which the medium vibrates in a direction parallel to the direction in which the wave travels.

Answer 9

Longitudinal wave;

Sound waves are longitudinal

Question 10

Phenomenon that occurs when two waves meet while traveling along the same medium.

Answer 10

Wave interference

Question 11

The pattern formed by superposition of different sets of waves that produces reinforcement in some places and cancellation in others.

Answer 11

Interference pattern

Question 12

A stationary wave pattern formed in a medium when two sets of identical waves pass through the medium in opposite directions.

Answer 12

Standing wave

Question 13

The shift in received frequency due to motion of a vibrating source toward or away from a receiver.

Answer 13

Doppler effect

Question 14

The V-shaped disturbance created by an object moving across a liquid surface at a speed greater than the wave speed.

Answer 14

Bow wave

Question 15

The cone-shaped disturbance created by an object moving at supersonic speed through a fluid.

Answer 15

Shock wave

Question 16

The loud sound resulting from the incidence of a shock wave.

Answer 16

Sonic boom

Question 17

A wiggle in time, but not in space, is a _________.

Answer 17

vibration

Question 18

Like a transverse wave, a longitudinal wave has _________, __________, ____________, and _______.

Answer 18

amplitude, frequency, wavelength, and speed.

Question 19

Which of the following is not a transverse wave: a) sound; b) light; c) radio; d) all of these; e) none of these

Answer 19

a) sound

Question 20

The vibrations of a longitudinal wave move in a direction: a) along the direction of wave travel; b) at right angles to the direction of wave travel; c) that changes with speed

Answer 20

a) along the direction of wave travel

Question 21

The frequency of a simple pendulum depends on: a) its mass; b) its length; c) the acceleration due to gravity; d) all of these; e) two of these

Answer 21

e) two of these;

The frequency of a simple pendulum depends on its length and the acceleration due to gravity.

Question 22

A standing wave occurs when: a) two waves overlap; b) a source wave and its reflected wave are in phase; c) the speed of the wave is zero or near zero; d) the amplitude of a wave exceeds its wavelength

Answer 22

b) a source wave and its reflected wave are in phase

Question 23

The Doppler effect is characteristic of: a) water waves; b) sound waves; c) light waves; d) all of the above

Answer 23

d) all of the above;

The Doppler effect is characteristic of water waves, sounds waves, and light waves.

Question 24

The pendulum with the greatest frequency is the pendulum with the: a) greatest mass; b) shortest length; c) least mass; d) greatest amplitude;

Answer 24

b) shortest length

Question 25

An object that completes 20 vibrations in 10 seconds has a frequency of: a) 0.5 hertz; b) 1 hertz; c) 2 hertz; d) 200 hertz

Answer 25

c) 2 hertz

Question 26

The vibrations of a transverse wave move in a direction:

Answer 26

at right angles to the direction of wave travel

Question 27

Wave interference occurs for: a) sound waves; b) light waves; c) water waves; d) All of the above

Answer 27

d) All of the above;

Wave interference occurs for sounds waves, light waves, and water waves.

Question 28

A Doppler effect occurs when a source of sound moves:

Answer 28

either towards you or away from you

Question 29

To say that one wave is out of phase with another is to say that the waves are: a) different amplitudes; b) different frequencies; c) different wavelengths; d) reaching maximum amplitude at different times; e) all of these

Answer 29

d) reaching maximum amplitude at different times

Question 30

A node is a position of:

Answer 30

minimum amplitude

Question 31

A sound wave has a frequency of 500 Hz. What is the period of vibration of the air molecules due to the sound wave: a) 1 s; b) 0.01 s; c) 0.002 s; d) 0.005 s;

Answer 31

c) 0.002 s;

Period = 1/frequency 
Period = 1/500 Hz = 0.002 s

Question 32

If the frequency of a particular wave is 20 Hz, its period is: a) 1/20 second; b) 20 seconds; c) more than 20 seconds; d) none of the above;

Answer 32

a) 1/20 second;

Note when F = 20 Hz,
T = 1/F = 1/20 Hz
T = 1/20 second

Question 33

A wave with wavelength 10 meters and time between crest of 0.5 second is traveling in water. What is the wave speed: a) 0.1 m/s; b) .2 m/s; c) .5 m/s; d) .20 m/s

Answer 33

d) .20 m/s

Question 34

The wavelength of a longitudinal wave is the distance between: a) successive compressions; b) successive rarefactions; c) both a and b; d) none of the above;

Answer 34

c) both a and b;

Successive compressions and successive rarefactions.