Newton's Laws of Motion

Newton's three laws of motion, in their classical statement, are:

First law: Every inanimate object continues to be in its state of rest, or of uniform (unaccelerated) motion in a straight line, unless and until it is acted upon by an external, unbalanced force.

Second law: The rate of change of linear momentum of a rigid body is directly proportional to the applied force and takes place in the direction of the applied force. In suitable (SI) units this becomes $\vec{F}=\frac{d\vec{p}}{dt}$, where $\vec{p}=m\vec{v}$ is the linear momentum.

Third law: To every action (force) there is an equal and opposite reaction (force). …