1. An audio speaker producing a steady sound at an outdoor concert is 20 ft away from you. If you move to a position where the speaker is 83 ft distant, by what factor will the amplitude of the sound change?

A_f

A_i

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2. Two children stretch a jump rope between them and send wave pulses back and forth on it. The rope is 2.9 m long, its mass is 0.48 kg, and the force exerted on it by the children is 51 N.

(a)What is the linear mass density of the rope (in kg/m)? kg/m

(b)What is the speed of the waves on the rope (in m/s)? m/s

3.A 3.6 Hz continuous wave travels on a Slinky. If the wavelength is 0.53 m, what is the speed of waves on the Slinky (in m/s)? m/s

4. A wave traveling 79 m/s has a wavelength of 4.4 m. What is the frequency of the wave (in Hz)?

5. A steel cable with total length 46 m and mass 140 kg is connected to two poles. The tension in the cable is 2,121 N, and the wind makes the cable vibrate with a frequency of 2 Hz. Calculate the wavelength of the resulting wave on the cable. m

6. In a student laboratory exercise, the wavelength of a 40,300 Hz ultrasound wave is measured to be 0.875 cm. Find the air temperature (in K). K

7.A person stands directly in front of two speakers that are emitting the same pure tone. The person then moves to one side until no sound is heard. At that point, the person is 5.40 m from one of the speakers and 5.44 m from the other. What is the frequency (in Hz) of the tone being emitted? (Assume air temperature to be 20C.) Hz

8. A sonic depth gauge is placed 3.0 m above the ground. An ultrasound pulse sent downward reflects off snow and reaches the device 0.013 seconds after it was emitted. The air temperature is 20C.

(a)How far (in m) is the surface of the snow from the device? (Round your answer to at least three significant figures.) m

(b)How deep (in m) is the snow? m

9.A baseball fan sitting in the "cheap seats" is d = 159 m from home plate (see the figure below). How much time elapses between the instant the fan sees a batter hit the ball and the moment the fan hears the sound? (Assume the speed of sound is 344 m/s, and the vertical distance can be ignored.)

10.The force stretching the D string on a certain guitar is 143 N. The string's linear mass density is 0.004 kg/m. What is the speed of waves on the string? m/s

11. A 220-Hz sound travels through pure hydrogen. The wavelength of the sound is measured to be 5.84 m. What is the speed of sound in hydrogen? m/s

12.Ultrasound probes can resolve structural details with sizes approximately equal to the wavelength of the ultrasound waves themselves. What is the size of the smallest feature observable in human tissue when examined with 15-MHz ultrasound? The speed of sound in human tissue is1,540 m/s. m

13.A sound pulse emitted underwater reflects off a school of fish and is detected at the same place 0.16s later (see the figure below). How far away are the fish? (Assume the water temperature is20C.) m

14.The sound level measured in a room by a person watching a movie on a home theater system varies from 60 dB during a quiet part to 100 dB during a loud part. Approximately how many times louder is the latter sound? times