If someone presses a pointed needle against your skin, you are hurt. But if someone presses a rod against your skin with the same force, you easily tolerate. Explain.
It is because of the pressure in the case of the needle is more than the pressure in the case of the rod. Suppose the same force F is applied in both cases. If the area of needlepoint =a and the area of the rod =A so that A>a. The pressure of needlepoint F/a >F/A. So the needlepoint hurts.
