Question

Rahul stands on a loose sand.His feet goes deep into the sand.But when he lies down on the sand,his body doesn't go deep in the sand.Explain why??

Answer 1

when he stands there is less area of contact and thus more pressure and he goes down.....but when he lies down his whole body is in contact and more area thus the pressure will be low so he does not go down...

pressure inversely proportional to area

Answer 2

due to pressure when he stand the force acting on sand is on very small area where as when he lay down the force uniformly distributed on sand so he doesn't go deep