Question
Question: A man squatting on the ground gets straight up and stands. The force of reaction of ground on the ma...
A man squatting on the ground gets straight up and stands. The force of reaction of ground on the man during the process is.
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
At first greater than mg, and later becomes equal to mg.
Explanation
Solution
In the process of getting straight up and stand from squatting position, the man exerts a variable force (F) on the ground to set his body in motion. This force is in addition to the force required to support his weight (mg). Once the man is in standing position, F becomes zero.