posted by rory on .
A hammer taps on the end of a 8.13m long metal bar at room temperature. A microphone at the other end of the bar picks up two pulses of sound, one that travels through the metal and one that travels through the air. The pulses are separated in time by 10.00ms. What is the speed of sound in this metal?(the speed of sound in air is 343 m/s)
Let the speed of sound in the metal be V. L = 8.13 m
Time of travel is L/343 for air and L/V for metal.
L(1/343 - 1/V) = 10.00^10^-3
1/343 - 1/V = 1.230*10^-3
1/V = 2.915*10^-3 - 1.230*10^-3
V = 593 m/s
That speed looks too low for sound in metal, but maybe they have chosen phony numbers for this problem.