Question

a boy lying on a mattress, stands up on it. he observes that the matress is now depressesd deeeper down. why does this happen?

Answer 1

Hey!

This is due to the pressure.
We know that,

Pressure= Force/Area
Pressure and area are inversely proportional.

Thus when the boy was lying on the mattress, the area was more and thus pressure was less. But when the boy stood on the mattress , the area became smaller and thus pressure increased, and thus mattress got depressed deeper.

Hope it helps...!!!