Question

Give scientific reasons for the following:

When a nail is hammered into a piece of wood, the noise of the hammering appears to get higher and higher in pitch.

Answer 1

Nail hammered into wood as the nail enters the wood, the free vibrating length of the nail decreases. The frequency of vibration of a rod/string is inversely proportional to its length. Hence, as length decreases, frequency increases, so the pitch appears to become higher and higher. \[f\propto \frac{1}{l}\]