Linear momentum - Aetherwisp

The linear momentum $\mathbf{p}$ , or just momentum, of an object with mass $m$ moving at a velocity $\mathbf{v}$ is the product

\mathbf{p}=m\mathbf{v}

A force $\mathbf{F}$ applied onto the object changes the momentum of the object according to Newton's second law:

\mathbf{F}=\frac{d\mathbf{p}}{dt}=\dot{\mathbf{p}}

also using dot notation for the derivative. From this we can immediately see the very important theorem of momentum conservation.

An equivalent theorem also holds for a system of particles:

External forces are those applied to the particles by external sources and not other particles. An example would be Earth's gravity acting on a basket of balls.