When small boy is trying to push a heavy stone, mention various forces acting on the stone.
The various forces acting on the stone are:
- The gravitational force exerted by the earth which pulls the stone downwards.
- The force of reaction exerted by the ground on the stone vertically upwards.
- The force of pushing exerted by the boy.
- The force of friction exerted by the stone.
When a small boy tries to push a heavy stone, then all these forces are balanced, and therefore the stone does not move.