Newton's three laws

Newton’s three laws form the heart of classical mechanics: the first defines inertial frames and the principle of inertia, the second links force, mass and acceleration ($\sum\vv F = m\vv a$), the third governs action–reaction pairs. Two historical interludes tell the story of the birth of the Principia and the mystery of inertial versus gravitational mass.

• First law (principle of inertia)
• Newton’s Principia
• Newton’s second law
• Mass: inertial or gravitational?
• Third law (action and reaction)
• Second law for a system

Try it — interactive simulation