17.2 Speed of Sound

Imagine you observe two firework shells explode. You hear the explosion of one as soon as you see it. However, you see the other shell for several milliseconds before you hear the explosion. Explain why this is so.

When sound passes from one medium to another where its propagation speed is different, does its frequency or wavelength change? Explain your answer briefly.

You may have used a sonic range finder in lab to measure the distance of an object using a clicking sound from a sound transducer. What is the principle used in this device?

What frequency sound has a 0.10-m wavelength when the speed of sound is 340 m/s?

(a) What is the speed of sound in a medium where a 100-kHz frequency produces a 5.96-cm wavelength? (b) Which substance in the table is this likely to be?

Air temperature in the Sahara Desert can reach $56.0 ° \text{C}$ (about $134 ° \text{F}$). What is the speed of sound in air at that temperature?

A sonar echo returns to a submarine 1.20 s after being emitted. What is the distance to the object creating the echo? (Assume that the submarine is in the ocean, not in fresh water.)

Suppose a bat uses sound echoes to locate its insect prey, 3.00 m away. (See the figure.) (a) Calculate the echo times for temperatures of $5.00 ° \text{C}$ and $35.0 ° \text{C} .$ (b) What percent uncertainty does this cause for the bat in locating the insect? (c) Discuss the significance of this uncertainty and whether it could cause difficulties for the bat. (In practice, the bat continues to use sound as it closes in, eliminat…