Question

describe the motion of a rocket on the basis of equation of continuity
A1v1=A2v2
Av=constant

Answer 1

define your variables

Answer 2

A1 = volume of gas generation
v1 = velocity of exiting gases thru restriction nozzle

A2 = volume of gases just at restriction nozzle A2<A1
V2 = velocity of gases just at restriction, V2>V1

This describes a rocket that is flying a vertical path where the gases generated compress and accelerate thru the nozzle and then the gases cool after the nozzle giving the rocket forward thrust

Answer 3

And since AV is a constant, that means it is a constant acceleration as the fuel burns up