2-2 Speed of Sound

A man strikes a long steel rod at one end. Another man, at the other end with his ear close to the rod, hears the sound of the blow twice (once through air and once through the steel rod), with a time interval between the two sounds of Dt = 0.1 s. What is the length L of the steel rod? For steel, Y = 2.1x1011 Pa, and the r = 7.0x103 kg/m3. Take the speed of sound in air vair = 340 m/s.

Example 1