Question

why do nails and bullets have pointed ends?

Answer 1

Step1: Definition of Pressure

1. Pressure is a measure of the effect of force.
2. Thrust acting on the unit surface of contact is termed what we refer to as pressure.
3. Thus, Pressure = Thrust / Area.
4. Now, from the definition, we see that the pressure or effect of force depends inversely on the area of contact.
   Thus, as an area of contact increases the pressure decreases and vice versa.

Step2: Understanding the question from the definition of pressure:

1. It is clear from the definition of the pressure that the pressure varies inversely with the area of contact.
2. i.e more the area of contactless is the pressure applied and the lesser the area of contact of a body more is the pressure applied.
3. Now, nails and bullets have pointed ends such that the area of the cross-section of the pointed end is very small.
4. Since nails and bullets are meant to pierce one's skin, due to the smaller contact areas they will apply more pressure on the skin and penetrate easily.
   Hence, nails, and bullets have pointed ends.