Inertial frame

An inertial frame is a reference frame that is not accelerating or rotating, where objects move with constant velocity unless acted on by a net external force.

A NASA space shuttle launches with fiery liftoff, ascending into the sky amid plumes of smoke.

Newton’s Second Law: Definition, Units, Applications & Examples

Newton’s Law of Motion through a friendly guide to Newton’s Second Law (F = ma): definition, units, and free-body diagrams. Real examples—cars, rockets, sports—plus misconceptions, quick problem steps, and FAQs. Boost exam confidence with practical tips rooted in Newton’s Law of Motion and everyday physics for students.