03 waves (solving)

Question 1

Formula

Period (T)

Answer 1

𝑻 =𝟐𝝅 √𝒎/k

Question 2

Formula

Frequency (f)

Answer 2

f = 1/T

Question 3

Formula

Wave Speed

Answer 3

𝒗 =𝝀/T or 𝒗 =𝝀f

Question 4

A pendulum swings back and forth, taking 0.5 s to complete one full cycle. What is the frequency of the pendulum’s vibration?

Answer 4

2hz

Question 5

A tuning fork vibrates at a frequency of 250 Hz. How long does it take to complete one full vibration?

Answer 5

0.004s (4ms)

Question 6

A heart beats once every 0.8 seconds. What is the frequency of the heart rate in Hertz?

Answer 6

1.25Hz

Question 7

If a specialized motor completes 20 full rotations in 5 seconds, what is its frequency?

Answer 7

4Hz

Question 8

A wave has a wavelength of 12 meters. If it takes 4 seconds for one full wave to pass a stationary point, what is the speed of the wave?

Answer 8

3 m/s

Question 9

A water wave has a wavelength of 24 meters and
travels at 4.8 m/s. What is the period of this wave?

Answer 9

5s

Question 10

If the wavelength of a wave was doubled while keeping its speed constant, what happens to the period?
A. The period is halved.
B. The period remains the same.
C. The period doubles.
D. The period quadruples.

Answer 10

C

𝒗 =𝝀/T –> 𝒗 =2𝝀/T = 𝒗 =2𝝀/2T = 𝒗 =𝝀/T

Question 11

A wave has a frequency of 20 hertz and a wavelength of 9 cm. What is the speed of the wave?
A. 0.0045 m/s
B. 0.45 m/s
C. 1.80 m/s
D. 180 m/s

Answer 11

C

𝒗 =𝝀f
𝒗 = .09(20)
𝒗 = 1.8

Question 12

What is the speed of the musical note “A” if it has a frequency of 440 Hz and a wavelength of 0.784 m?
A. 561 m/s
B. 56.1 m/s
C. 345 m/s
D. 34.5 m/s

Answer 12

C

𝒗 =𝝀f
𝒗 = 440 (0.784)
𝒗 = 440 (~1)
v < 440

Question 13

A mass-spring system undergoes simple harmonic motion with a spring constant equal to 200 N/m and a mass equal to 2 kg. What is the period of the oscillation?

A. 0.06 s
B. 0.40 s
C. 0.60 s
D. 1.00 s

Answer 13

C

Question 14

Sound waves are transmitted better in __________.
A. gases than in solids
B. liquids than in solids
C. gases than in liquids
D. solids than in liquids

Answer 14

D

Question 15

A guitar string is found to produce two consecutive resonant frequencies of 330 Hz and 396 Hz. What is the fundamental frequency of this string?

Answer 15

66

Question 16

If the wavelength of the fundamental frequency is 1.2 m, what is the speed of the wave on the string?

Answer 16

79.2

Question 17

If the fundamental frequency of a wire is 45 Hz, what is the frequency of the fifth harmonic?

Answer 17

225

Question 18

A light ray strikes a flat mirror at an angle of 35° with the surface of the mirror. What is the angle of reflection relative to the normal?
A. 35°
B. 45°
C. 55°
D. 90°

Answer 18

55°

Question 19

If the total angle between the incident ray and the reflected ray is 130°, what is the angle of incidence?
A. 90°
B. 65°
C. 50°
D. 25°

Answer 19

65°

Question 20

Which of the following describes the ‘normal’ in the context of reflection?
A. A line perpendicular to the mirror’s surface at the point of incidence.
B. A line parallel to the mirror’s surface.
C. A line that shows the path that light takes before hitting the mirror.
D. A line that shows the path that light takes after
hitting the mirror.

Answer 20

A

Question 21

A hunter is standing on the edge of a river trying to spear a fish. Where should he aim to catch the fish?
A. Exactly where he sees the fish
B. Below where he sees the fish
C. Above where he sees the fish
D. It does not matter where he aims.

Answer 21

B

Question 22

Formula

Index of Refraction

Answer 22

n = c/v

Question 23

A beam of light travels through a certain type of
glass at a speed of 2.0×108 m/s. What is the index of refraction for this glass?

Answer 23

1.5 m/s

Question 24

If a substance has an index of refraction of 1.33 (like water), what is the speed of light within that
substance?

Answer 24

2.25 x 10^8

Question 25

In the spectrum or band of colors, violet is the least visible because it __________. A. is the most refracted B. is the least refracted C. is not refracted D. just wants to be seen

Answer 25

A

Question 26

# Formula Sound wave (v)

Answer 26

v = 331 + 0.6T

Question 27

# Formula Doppler Effect

Answer 27

𝒇𝟎 = 𝒇𝒂 (𝒗±𝒗𝒐 / 𝒗±𝒗s) ## Footnote 𝒇𝟎 = observed frequency 𝒇𝒂 = actual frequency 𝒗= speed of sound wave 𝒗𝒐 = speed of the observer (+ if towards; - if away) 𝒗𝒔 = speed of the source (+ if away; - if towards)

Question 28

One day when the temperature is 15.0 °C, an explosion occurs at a distance of 6.0 km from a person. How long after the explosion does the person hear it?

Answer 28

17.65

Question 29

A car moving at 20.0 m/s is approaching a factory whistle that has a frequency of 500 Hz. If the speed of sound in air is 340 m/s, what is the apparent frequency of the whistle as heard by the driver? A. 500 Hz B. 510 Hz C. 520 Hz D. 530 Hz

Answer 29

510m

Question 30

A car moving at 20 m/s with its horn blowing (f = 1200 Hz) is chasing another car going at 15 m/s in the same direction. What is the apparent frequency of the horn as heard by the driver being chased? Take the speed of sound to be 340 m/s.

Answer 30

D

Question 31

The pitch of a sound depends on the wave’s __________.

Answer 31

frequency

Question 32

The loudness of a sound depends on the wave’s __________.

Answer 32

amplitude