Eli5 Why is force equal to mass multiplied by acceleration and not speed ?

Question

If a car moves consistently at 80 kmh and it weighs at 600kg, is it not generating any force? since you know, a=0, am I stupid or is Newton ?

In: 13

Answer 1

Force is defined as the rate of change of momentum. Momentum is the product of mass and velocity. Mass is a constant for a given object at this level. So force is the product of the mass and the rate of change of velocity – and rate of change of velocity is known as acceleration.

All of this stuff gets much easier when you can use calculus: a lot of the formulas to memorise in mechanics are just special cases of standard results from calculus.