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 ($\overrightarrow{F}=m\overrightarrow{a}$)
• Third law: For every force, there is an equal and opposite reaction force (${\overrightarrow{F}}_{\mathrm{a}b}=-{\overrightarrow{F}}_{\mathrm{b}a}$)

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