Question

Explain the following :

a. Why can't we hammer a nail by its head on the wood?

b. A sharp knife cuts better than a blunt knife. Why?

Answer 1

We know that pressure = $\frac{Force}{Area}$

a. The head of the nail has a larger area than the tip so the pressure is reduced if we try to push the head into the wood.

b. A sharp knife has a lesser surface area than blunt one, so, a sharp knife applies a greater pressure when used for cutting.