3) Calculate the velocity of longitudinal waves in a thin aluminum bar. E = 7.0 1010 N / m and rho = 2.7 103 kg

3) Calculate the velocity of longitudinal waves in a thin aluminum bar. E = 7.0 1010 N / m² and rho = 2.7 103 kg / m³ 

An analog formula for the phase velocity applies to three-dimensional longitudinal waves in an elastic medium. 

In that case, the compression modulus K must be used instead of the Young's elasticity modules: