Question

Name The Principal on which a rocket work?

Answer 1

A rocket works on the principal of Newton's third law of motion, that is " FOR EVERY ACTION THERE IS EQUAL AND OPPOSITE REACTION". Here  the action  is that the rocket releases air and the opposite reaction is that it moves oppositely that is up.

Answer 2

Rocket works on the principle of Newton's Third law" i,e for every action there is equal and opposite reaction.
Explanation:
In a rocket, hot gases produced by the rapid burning of fuel rush out of jet at the bottom of rocket at very high speed . The equal and opposite reaction force of downward going gases pushes rocket upwards with great speed.
We can also say that Rocket works on the principle  of law of conservation of momentum