Question

The principle of rocket propulsion depends on :

• A. Newton's third law of motion
• B. Principle of conservation of momentum
• C. Either A and B
• D. Both A and B

Answer 1

The correct option is D Both A and B

The principle of rocket propulsion works on the 'Newton's Third Law of Motion'. It states that, 'to every action, there is always an equal and opposite reaction'.

In the case of a rocket, the engine emits hot burning gases in the downward direction. These gases apply an equal and opposite reaction force to the rocket in the upward direction.

This is how a rocket is propelled.

The principle of conservation of momentum states that whenever two bodies collide or get separated, then their total momentum before collision or separation is equal to their total momentum after collision or separation.

Since the gases of the rocket and the rocket are stationery at the start, their total momentum is zero. After the gases start burning, the momentum imparted to the rocket is equal and opposite to that of the gases. Hence their total momentum is zero.