On which conservation law does a rocket work?

Question

A body of mass 2 kg is moving with a velocity of 3 m/s. What is its kinetic energy?

Answer 1

Picture the rocket and its exhaust gas as one combined system with no outside push acting on it.

Before firing, the system has some total momentum, possibly zero if it is standing still.
When fuel burns, gas shoots out backward carrying momentum in that direction.
Because no external force acts along the axis, the total momentum of gas plus rocket must stay unchanged.
So the rocket body must move forward with a momentum exactly equal and opposite to the momentum of the ejected gas.

This forward push, arising purely from momentum staying constant for the whole system, is why a rocket works on the conservation of linear momentum. Option C is correct.

Answer 2

Picture the rocket and its exhaust gas as one combined system with no outside push acting on it.

Before firing, the system has some total momentum, possibly zero if it is standing still.
When fuel burns, gas shoots out backward carrying momentum in that direction.
Because no external force acts along the axis, the total momentum of gas plus rocket must stay unchanged.
So the rocket body must move forward with a momentum exactly equal and opposite to the momentum of the ejected gas.

This forward push, arising purely from momentum staying constant for the whole system, is why a rocket works on the conservation of linear momentum. Option C is correct.

On which conservation law does a rocket work?

Show Hint

The Correct Option is C

Solution and Explanation

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