Dynamics — Newton's Laws & Momentum

Newton's laws of motion

1. First law — a body remains at rest or moves with constant velocity unless acted on by a resultant force.
2. Second law — the resultant force is equal to the rate of change of momentum: $F = \dfrac{\Delta p}{\Delta t}$. For constant mass this reduces to $F = ma$.
3. Third law — if body A exerts a force on body B, then B exerts an equal and opposite force on A (the forces act on different bodies and are of the same type).