Can Time Travel Truly Allow Us to Visit the Past?

[Gokul43201]

Omin, you are using terms that are undefined and have no rigorous physical sense. But in any case, Ba has provided two valid cases where the resultant of several forces being zero does not mean that the forces can not be detected.

 

[omin]

I found that quote funny.

Anyways, energy is NOT force.

People often get confused about this concept because of electricity. They 'use' electricty. Real energy never gets 'used'. The kinetic energy in something can move it forever!

A good example is this: if energy is exchanged or expended because of forces, what happens to a rope strung between two walls? (taught) We'll say this rope won't ever break. Since there is a force being exerted on the rope it must eventually 'run out' of energy right? Then what, it can't pull at all? You could start pulling at that rope and stretch it forever!

Also, acceleration does not imply speed, it implies CHANGE in speed. Energy does not imply force and force does not imply energy. Think of it this way: I accelerated at 5 kajillion meters per second per second for 0 seconds.

How much did my speed change? Well duh, 0. There was no time for it to happen! It's THE SAME THING for force and energy. There was no distance for the energy to change over!

Don't believe me? Look at the units. Speed is acceleration * time. Energy is force * distance. For change in speed from acceleration you need time. For change in energy from force YOU NEED DISTANCE.

Euclid made a point about the point. Is this the one you are trying to make?