Why are Newton’s Laws of Physics called laws and not theories?

Question

Why are Newton’s Laws of Physics called laws and not theories?

In: Physics

Answer 1

There isn’t an exact answer but generally a law tells you *what* will happen. A theory tells you *why* it happens.

So Newton’s second law of motion, F = d(mv)/dt, tells you how forces relate to changes in momentum; if you push something it will accelerate. But it doesn’t tell you *why* forces lead to a change in momentum.

Similarly his Law of Universal Gravitation tells you (roughly) what will happen if you put two things with mass near each other, but won’t tell you why it does that.