A man squatting on the ground gets straight up and stand. 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
When the man gets straight up and stand in this process initially for the man to move upward he needs a net external force in the upward direction which can only be provided by the normal reaction(N) from the ground. Therefore, N−mg>0⇒N>mg (initially) and later when he stands up and becomes static then N=mg
