I think that Newton's law is incorrect.?

Question

If a body is moving with uniform velocity,so it have 0 acceleration.In the example i created, a body is moving with uniform velocity and the force applied to it is lets say 10 N.what will be the mass of the body?solve it with ;
F=ma

Answer 1

Unless you are doing quantum mechanics or relativity, newtonian mechanics are fine.

If you apply a net force to a body, it will accelerate (since it can't be infinitely massive), so the premise of your problem is flawed.

Answer 2

If the net force on a body is 10 N, it will not be moving with uniform velocity.

It's like saying that I have a number x such that 2x = 5 and 3x = 10. Just because I'm saying it doesn't mean it's a valid example, and the fact that there's no solution doesn't mean mathematics is invalid, it just means the example is invalid.

Of course, you could have a body moving with uniform velocity with an applied force of 10N, as long as there are other forces acting on the body with a combined total of 10N in the direction opposite to the first force, so that the total net force on the body is 0.

Answer 3

Yes, F=ma (and you can't push on a rope).

So what's the problem? Unless you're talking relativistic speeds, Newtonian dynamics work just fine.

Doug

Answer 4

You don't understand physic at all !

Answer 5

ohh i see