Chapter 12 Terms

Question 1

Periodic motion

Answer 1

Recurring back-and-forth or cyclical motion of a system in a regular time interval.

Question 2

Rest position

Answer 2

The position of an oscillating system exactly halfway between the maximum displacements of its oscillations.

Question 3

Amplitude

Answer 3

The maximum displacement from the rest position of a system experiencing periodic motion.

Question 4

Cycle

Answer 4

One complete back-and-forth motion or rotation in periodic motion, where the system has returned to its starting point.

Question 5

Period (T)

Answer 5

The time it takes to complete one cycle.

Question 6

Frequency (f)

Answer 6

The number of oscillations or other periodic changes completed per unit of time.

Question 7

Restoring force

Answer 7

The force that acts on an oscillating system to return it to its rest position.

Question 8

Damping

Answer 8

Reducing the amplitude of periodic motion through friction or other resistance.

Question 9

Resonance

Answer 9

The condition of an oscillating system when its amplitude increases due to reinforcement by energy added at its natural frequency.

Question 10

Natural frequency

Answer 10

The frequency at which an oscillating object experiences resonance.

Question 11

Pendulum

Answer 11

A mass attached to the end of an arm suspended from a pivot point that is free to swing back and forth under the influence of gravity or other forces.

Question 12

Foucault pendulum

Answer 12

A pendulum first constructed by Jean Foucault in 1851 to demonstrate that the earth rotates on its axis.

Question 13

Wave

Answer 13

An oscillation in matter or mutually interacting electromagnetic fields that transfers energy from one place to another.

Question 14

Mechanical wave

Answer 14

A wave that travels through matter by the periodic motion of its particles.

Question 15

Crest

Answer 15

Compared to the rest position in a wave- form, the highest point of a wave (as in water waves) or the location of greatest particle density (as in sound waves).

Question 16

Trough

Answer 16

The lowest point of a wave compared to the rest position (as in water waves) or the location of least particle density (as in sound waves).

Question 17

Wavelength

Answer 17

The distance between corresponding points on adjacent waveforms, such as crest-to-crest or trough-to-trough.

Question 18

Medium

Answer 18

Matter that oscillates as a wave travels through it.

Question 19

Pulse

Answer 19

A single wave cycle or a very short burst of waves.

Question 20

Transverse wave

Answer 20

A wave in which the oscillations are at right angles to the direction of wave travel.

Question 21

Longitudinal wave

Answer 21

A wave in which the oscillations are parallel to the direction of wave travel.

Question 22

Compression

Answer 22

In longitudinal waves, regions of maximum particle density.

Question 23

Rarefaction

Answer 23

In longitudinal waves, regions of minimum particle density.

Question 24

Reflection

Answer 24

Phenomenon of a wave bouncing off a surface.

Question 25

Refraction

Answer 25

Phenomenon that occurs when a wave’s speed changes as it moves through a boundary between different media .

Question 26

Interference

Answer 26

The interaction of two or more intersecting waves, resulting in a net waveform with amplitudes and periods different from those of the interacting waves.

Question 27

Constructive interference

Answer 27

The interaction of interfering waves resulting in a waveform with a larger amplitude than those of the interfering waves.

Question 28

Destructive interference

Answer 28

The interaction of interfering waves resulting in a waveform with a smaller amplitude than those of the interfering waves.

Question 29

Standing wave

Answer 29

A waveform whose nodes appear to be stationary and whose crests and troughs periodically alternate between the nodes.

Question 30

Node

Answer 30

A point in a standing wave that experiences no vertical displacement.

Question 31

Beat

Answer 31

A large-amplitude, slowly varying wave that is the result of interference between two continuous waves having slightly different wave lengths.

Question 32

Diffraction

Answer 32

The bending of waves around the edges of objects or after passing through openings or gratings.

Question 33

Doppler effect

Answer 33

The perceived difference in received frequency compared to the frequency of a wave source due to the relative motion of the observer and the source.