What do you mean by conservation of mechanical energy? State the condition when it holds.

Give one example to show that the sum of potential energy and kinetic energy remains constant if friction is ignored.

A ball is made to fall freely from a height. State the kind/kinds of energy possessed by the ball when it is:

(a) at the highest point

(b) just in the middle

(c) at the ground.

A truck starts from rest on a plane road. What are the possible energy changes taking place while the truck is in motion?