What must be the stress `(F//A)` in a stretched wire of a material whose Young's modulus is `Y` for the speed of lonitudinal waves equal to `30` times the speed of transverese waves?

Explanation

To solve the problem, we need to find the stress \( \frac{F}{A} \) in a stretched wire of a material whose Young's modulus is \( Y \), given that the speed of longitudinal waves is 30 times the speed of transverse waves.

### Step-by-step Solution:

1. **Understand the relationship between wave speeds and Young's modulus**:
- The speed of longitudinal waves \( v_L \) is given by the formula:
\[
v_L = \sqrt{\frac{Y}{\rho}}
...