Question

Why do you think it is necessary to define a separate quantity called pressure? Why is defining only force not enough?

Answer 1

It is necessary to define pressure as a separate quantity in order to evaluate the force acting on a surface. To measure and describe the effect of a force acting on a surface, we need both the amount of force applied and the area over which it is applied. So, only force is not enough for this purpose. We need a quantity that includes both the above things, and this quantity is pressure, which is defined as the force exerted per unit area.