Momentum, Its Conservation and Jet Propulsion
Why a rifle kicks back, why a rocket flies in empty space, and the one quantity that stays constant through every collision
Big Idea: Every moving body carries a "quantity of motion" called momentum, equal to its mass times its velocity. Inside a closed system the total momentum never changes, no matter how the bodies push, pull or collide. This single rule explains recoil, rockets and the motion of satellites.
By the end you will be able to:
- define momentum p = mv and state its unit and vector nature;
- connect the impulse of a force F·t to the change of momentum;
- state and apply the law of conservation of momentum for a closed system;
- explain recoil and jet (reactive) propulsion;
- describe how rockets accelerate and how satellites stay in orbit.