system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 Why is force equal to mass multiplied by acceleration and not speed ?

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 ?
gpt
Newton's first law: an object in motion will stay in motion unless a force acts upon it. An object flying through space at a constant speed has no force acting upon it. 

There's two things that may make this a bit confusing here on Earth. 

First of all, any thing in motion constantly has forces acting to slow it down like air resistance and friction so, unlike in our simple scenario, you do need to apply a force to keep it moving at a constant speed.

And the second is that as soon as the object runs into anything else, it'll exert a force on that object (causing it to slow down). So any time you try to interact with a moving object, you cause a force to happen.  But the force it exerts depends on how fast it decelerates, so it's still about acceleration. That's why modern cars crumple in a crash- by making it take longer for the car to decelerate to 0, the force on you will be lower.