24. Answer in detail II

The propulsion of rockets is based on the  and

Rocket propulsion:

Rockets are filled with fuel (either liquid-state or solid-state) in the propellant tank. This fuel is burnt when the rocket is fired, and the hot gas is ejected with high speed from the rocket's nozzle, producing a huge momentum.

 

An opposite reaction forceequal and opposite reaction forceequal force is generated in the combustion chamber to balance this momentum, making the rocket project reverseforward.

 

While in motion, the rocket's mass constantly decreases until the fuel is fully burnt out. Since there is no net external force acts on the system, the linear momentum of the system is conserved.

 

The rocket's mass decreases with altitude, resulting in the progressive decrease increase  in velocity of the rocket. At one particular stage, it reaches a velocity, which is adequate to just escape from the Earth's gravitational pull. This velocity is known as escape velocity.

 

• The acceleration of a rocket depends on three important factors: Exhaust velocityInlet velocity, the rate the exhaust is ejected, and the acceleration of the rocketmass of the rocket.
• To achieve the high speeds required to hop continents, obtain orbit, or escape Earth's gravity altogether, the rocket's mass other than fuel must be as small as possible.