Conservation of momentum explains why a gun or cannon recoils backwards when it is fired. When a cannon is fired, the cannon ball gains forward momentum and the cannon gains backward momentum.

When two objects collide the total momentum before the collision is equal to the total momentum after the collision (in the absence of external forces). This is the law of conservation of momentum.

By completing this specialization, you will be able to: M odel spacecraft with angular momentum exchange devices A nalyze methods to derive equations of motion Apply Holonomic and Pfaffian constraints ...

In general relativity, the energy–momentum tensor is considered to be ... For example, in string theory, Einstein's classical ...