Calculate the speed of longitudinal waves in

VIDEO TRANSCRIPT

This is Giancoli Answers with Mr. Dychko. The speed of a longitudinal wave in a liquid is the square root of its bulk modulus divided by its density. So, the bulk modulus of water is 2.0 times 10 to the 9 newtons per square meter and divided by the density of water 1.0 times 10 to the 3 kilograms per cubic meter. That gives about 1400 meters per second. And then for the speed in granite, it's a solid, so we take the square root of the elastic modulus divided by density. That's 45 times 10 to the 9 newtons per square meter for granite divided by its density of 2.7 times 10 to the 3 kilograms per cubic meter. And that gives 40100 meters per second for the speed of sound. And for a longitudinal wave in steel, is this whole again, so, same formula. And we have elastic modulus of steel is 200 times 10 to the 9 newtons per square meter divided by density of steel of 7.8 times 10 to the 3 kilograms per cubic meter and that gives a speed of 5100 meters per second.