Question

A pile driver drives posts into the ground by repeatedly dropping a heavy object on them. Assume the object is dropped from the same height each time. By what factor does the energy of the pile driver-Earth system change when the mass of the object being dropped is tripled?

Answer 1

Answer:Three times

Explanation:

The change in the energy of pile driver-Earth system is given by change in Potential energy

Potential energy is given by

$P.E.=mgh$

where m=mass of object

g=acceleration due to gravity

h=height from which object is dropped

When mass of object being dropped is tripled then Potential energy is tripled

i.e. $P.E.=3\times mgh$

Thus energy is multiplied by a factor of 3