Physics with Calculus/Mechanics/Newton's Laws

Newton's laws describe what causes motion of objects. There are three laws, which can be briefly stated:


 * First law: In an inertial reference frame, unless acted on by a net force, an object at rest stays at rest.
 * Second law: In an inertial reference frame, force is equal to mass times acceleration ($$\vec{F} = m \vec{a}$$)
 * Third law: For every force, there is an equal and opposite reaction force ($$\vec{F}_{\mathrm ab} = - \vec{F}_{\mathrm ba}$$)

Each of these laws will be discussed in more detail in each section.