A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is.

Options

A. constant and equal to `mg` in magnitude.
B. constant and greater than `mg` in magnitude.
C. variable but always greater than `mg`.
D. at first greater than `mg`, and later becomes equal to `mg`

Answer

D

Explanation

When the man gets straight up and sstand, reaction of ground on the man `=`mg. However, when he is squatting on the ground, reactio of ground is more than `mg`, as the man is to exert sone extra force on the ground to stand up .