Question

When we jump on a concrete surface the feet are more seriously hurt than while jumping on sand

Answer 1

Reason:
1 .If a man falls on a soft landing site like heap of sand, the man takes
a longer time to come to stop.
2. The rate of change of momentum is less due to which a smaller stopping force acts on the man and he does not get hurt.
Thus, Sand ,being soft reduces,the man's monentum more gently.

3. If the man lands on hard ground like cement floor, then his momentum will be reduced to zero in,very short time .
4. The rate of change of momentum will be large due to,which a large opposing force,will act on the man.
5. This force,can lead to serious injuries to the man.

Answer 2

concrete surface is a hard surface which doesn't absorb the energy of gravitation when we fall down so we get hurt more badly ....but sand is not as hard as concrete so it absorbes the energy of gravity and we don't get hurt badly.. (if its wrong please comment)