Forza

Meet Forza, a push that makes a cart speed up.

Newton's second law links force and motion: the net force on an object equals its mass times its acceleration, F = ma. A bigger force gives a bigger acceleration, and a heavier object accelerates less for the same force. Force and acceleration are vectors and point the same way. Newton set this out in his Principia in 1687, and the newton, the SI unit of force, is the force that accelerates 1 kg at 1 m/s².

A 1000 kg car pushed by a net force of 2000 N accelerates at a = F/m = 2000 / 1000 = 2 m/s², gaining 2 m/s of speed every second.

Engineers use F = ma to design brakes, engines, aircraft and safety systems, and it is the starting point for calculating the motion of almost anything, from a thrown ball to a rocket.

The force in the formula is the net force, the sum of all forces; pushing a stuck crate does nothing if friction cancels the push. For speeds near the speed of light, relativity changes the relationship, and for objects whose mass changes, like rockets, momentum is the safer quantity to use.