Non-Destructive Testing (NDT) Practice Test

If the longitudinal velocity in aluminum is .2500 in/us, what is the shear velocity?

1. .1750 in/us

2. .1250 in/us

3. .1000 in/us

4. .2000 in/us

The correct answer is: .1250 in/us

To determine the shear velocity in aluminum given the longitudinal velocity, it's important to understand the relationship between longitudinal waves and shear waves in isotropic materials like aluminum. The longitudinal wave velocity is typically denoted as \( V_L \) (in this case, 0.2500 in/us), and the shear wave velocity is denoted as \( V_S \). The relationship between these velocities is governed by the following formula: \[ V_S = \frac{V_L}{\sqrt{2}} \] This equation arises from the definitions and properties of wave propagation in materials, where shear waves travel slower than longitudinal waves due to the different modes of particle movement. Using the provided longitudinal velocity: \[ V_S = \frac{0.2500 \text{ in/us}}{\sqrt{2}} \] Calculating this gives: \[ V_S \approx 0.2500 \text{ in/us} \times 0.7071 \approx 0.1768 \text{ in/us} \] When considering the closest choice available, 0.1750 in/us would match best with our calculation, which suggests that the logic behind arriving at the value for the shear velocity is sound. The provided option meshes with the