Question

Rockets travel by pushing fuel backwards at high velocity. Which of the following does this demonstrate?

A) Conservation of energy

B) Conservation of velocity

C) Conservation of momentum

D) Newton's second law: F = ma

Answer 1

Rocket works on the conservation of momentum. In a rocket, the fuel burns and produces gas at high temperature. These gases are ejected out of the rocket from a nozzle at the back side of the rocket with high speed. Conservation of momentum dictates that if material (gas) is ejected backward, the forward momentum of the remaining rocket must increase since an isolated system (rocket + fuel) cannot change its net momentum.

Therefore, the correct option is (C) i.e.

C) Conservation of momentum