For example, an elephant has no momentum when it is standing still. When it begins to walk, it will have momentum in the same direction as it is travelling. The faster the elephant walks ...

A+B together allows us to make the impact force internal (and not appear in the linear impulse-momentum equation). FBDs for A and B individually allows us to determine the t-direction components of ...

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.