Question

If we jump from one or two stairs we don't get hurt but if we jump from a building we get hurt .Why?

Answer 1

As the height increases,
Potential energy increases.

When we jump from the top of the building,
Height is more and hence more potential energy will be converted to kinetic energy.

As the kinetic energy increases, velocity at which we reaches the ground will increase.
(K.E=(1/2)×M×V^2)

As the velocity increases,
Momentum also increases.
So when we jump from more height, velocity will be high and hence momentum will be more

This momentum cause pain.