NEWTON'S THIRD LAW

The law states that "to every action there is an equal and opposite reaction and these forces act on different bodies"

Examples

1. When a rocket is launched, the burnt gases are expelled down from the rocket body. Here action is on gases by the rocket body. Hence the gases exert an equal an opposite force on the rocket body in the upward direction. This is the reaction force. With this force rocket moves in upward direction.

ACTION...on the gases by the Rocket body.
REACTION..On the rocket by the burnt gases.

2. When a gun fires bullets, action is on the bullets by the gun and reaction on the gun by the bullets. Gun recoils back due to the reaction.

ACTION: On the bullets by the gun..
REACTION...on the gun by the bullets