The question the 3rd law poses is why does something stay at rest and it's a serious question.

if if we have a force Fab and its countered by a force -Fba you can write

Fab - Fba = 0 = F the net result is zero

In a world without the law you can end up with

Fab + Fba = F

Something can exert a force back on itself.

You can't reach down grab your ankles and lift you body off the ground ... you are imparting a force into your ankles and pulling them up .... so why don't they move?

Remember you have no forces resisting it in your case Finiter that force should do something.

See it's not an inconsequential law ... it's a deductive law because a force can not exert on itself.

As per Bill's definition a force is the transfer of energy, ergo energy can not create more energy, ergo no perpertual motion.

The 3rd law is a statement of the 1st law of energy in a mechanical/physical system.

Last edited by Orac; 09/06/11 05:11 AM.
I believe in "Evil, Bad, Ungodly fantasy science and maths", so I am undoubtedly wrong to you.