# Looking for a clear distinction between laws and kinematics

1. Aug 9, 2013

### SamRoss

Can anyone define the distinction between the laws of nature and the kinematics of nature? I am thinking that laws have more to do with forces and potentials and kinematics have more to do with velocities and reference frames but I cannot formulate a clear definition of one that does not overlap with the other. Is there a distinction or should I not even bother?

2. Aug 9, 2013

### MikeGomez

Kinematics by definition has to do with motion, so unless you can find a law of nature that is not concerned with motion, you are correct and should not even bother.

3. Aug 9, 2013

### AgentSmith

Kinematics is a subset of Newton's Laws. That is, kinematics are a consequence of Newton's Laws. You can also talk about relativistic kinematics being a consequence of Newton's Laws as modified by relativity.

4. Aug 10, 2013

### jfizzix

The laws of nature would be where the equations of motion come from (i.e. principle of least action, conservation laws, etc). The application of these equations if motion is kinematics of one kind or another.

5. Aug 10, 2013

### AgentSmith

True, which is what I said in a different way. You could also approach things from Lagrangian mechanics, probably ending up with Hamiltonian kinematics. But he was dealing with Newtonian mechanics, so I kept to that. As you know, some pre-Newton scientists had worked out some kinematic equations on a strictly empirical basis, but Newton showed where these came from, in the nonrelativistic, low gravity field instances.
(Then this guy named Albert messed up everything.)