Question

1) An echo bounces back from a building 1.55 s after you honk your horn. How many feet away is the building if the air temperature is 27.1°C?

2) A student under water clicks two rocks together and makes a sound with a frequency of 604.0 Hz and a wavelength of 2.4 m. What is the speed of this underwater sound?

3) You see condensed steam expelled from a ship's whistle 6.75 s before you hear the sound. If the air temperature is 26.2°C, how many meters are you from the ship?

4) v_{(sound, fresh water, 25.0}° _C) = 1,497 m/s

v_{(sound, seawater, 25.0}°_C) = 1,530 m/s

Compare the distance traveled in 7.50 s as a given sound moves through

(a) water at 25.0°C and km

(b) seawater at 25.0°C. km

5) A tuning fork vibrates 415.0 times a second, producing sound waves with a wavelength 81.7 cm. What is the velocity of these waves?

6) The distance between the center of a condensation and the center of an adjacent
rarefaction is 49.00 cm. If the frequency is 321.3 Hz, how fast are these waves moving? ×10 (select)0−2−4246 cm/s

7) A warning buoy is observed to rise every

7.7 s

as crests of waves pass by it.

(a) What is the period of these waves? s

(b) What is the frequency? Hz

8) How many seconds will elapse between seeing lightning and hearing the thunder if the lightning strikes 2.0 mi (10,560 ft) away and the air temperature is 87.8° F?

9) A 643.4 Hz sound has a velocity of 1,099.0 ft/s in the air and a velocity of 5,055.2 ft/s in water. Find the wavelength of this sound in

(a) air and ft

(b) the water. fts

Answer 1

1)Given,

t = 1.55 s ; T = 27.1 deg C

we know that speed of sound is related to temp as:

v = 331.4 + 0.6 Tc = 347.66 m/s

we know that, v = d/t => d = vt

d = 347.66 x 1.55 = 538.873 m = 1768 m

Hence, d = 1768 ft

2)Given,

f = 604 Hz ; lambda = 2.4 m

We know that

v = f lambda

v = 604 x 2.4 = 1449.6 m/s

Hence, v = 1449.6 m/s

3)Given,

t = 6.75 s ; T = 26.2 deg C

we know that speed of sound is related to temp as:

v = 331.4 + 0.6 Tc = 347.12 m/s

we know that, v = d/t => d = vt

d = 347.12 x 1.55 = 538.036 m

Hence, d = 538.036 m