Question

A hammer taps on the end of a 4.00 m long metal bar at room temperature. A microphone at the the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through air. The pulse traveling through the metal arrives 9ms earlier because sounds travels faster through solids than air. What is the speed of the sound in the metal? Speed of sound through air is 343 m/s at room temperature. Give your answer in units of m/s but do not include units,

Answer 1

Answer:

$v_m=193.5939\ m.s^{-1}$

Explanation:

• distance travelled by the sound, $l= 4\ m$

• speed of sound in air, $v_a=343\ m.s^{-1}$

• difference of time time between the two pulses of sound, $\Delta t=0.009\ s$

Now, we find the time taken by the sound in air to travel the given distance:

$t_a=\frac{l}{v_a}$

$t_a=\frac{4}{343}$

$t_a=0.011662\ s$

∴Time taken by the sound sound waves in the metal bar to travel the given distance:

$t_m=t_a+\Delta t$

$t_m=0.011662+0.009$

$t_m=0.020662\ s$

The speed of sound in the metallic bar:

$v_m=\frac{l}{t_m}$

$v_m=\frac{4}{0.020662}$

$v_m=193.5939\ m.s^{-1}$