Question

If the earth stops rotating, the weight of a body would increase or decrease if it is so then what is the explanation behind this??

Answer 1

if the earth stops rotating , weight of the body would increase. There are 2 forces acting on a person standing on the surface of earth . 1 . force of gravity acting downward towards center of earth , 2. centrifugal force due to earth rotation which acts upward ,away from center of earth . weight of a person = force of gravity - centrifugal force.
if earth stops rotating , centrifugal force disappears or goes to zero . so net weight would increase.