Question

state the principle behind the working of a rocket explain its working in brief

Answer 1

force of friction action

Answer 2

Principle of rocket is basically Newton's third law,the force which is exerted by the gases of rocket to the ground, the ground exert equal and opposite force on rocket hence resulting in upward acceleration of rocket
The rate of amount of gases which comes out in time t makes a contribution in upthrust of the rocket and since mass of rocket is continuously decreasing it provides sufficient upthrust!