Originally Posted By: paul
so what is the thing it had that it transfered twice?

Neither mass nor velocity but the product of them.

Quote:
I just replaced the turn that was giving the pipe
the +4000N force with a full stop decelerator that gives the pipe a +4000N force.

A change of direction has the same effect on the pipe as a stop? How can you possibly imagine that to be true? What if we stop it, then accelerate it in the opposite direction. Will that give +8000N while a U-bend is only +4000N?



Quote:

so guess what , if it takes a million years or 1 second for the spring to expand , the solar sail will still have
only -40N momentum because if you multiply its velocity x its mass its momentum will equal -40N

Are you seriously saying that applying the same force for a longer time will give the same momentum to an object?

Did you ever try pushing a car? Or anything at all for that matter? Don't say it has to have a spring, everything has a spring, just it's often very stiff and only compresses a short distance.

As soon as you start applying the 40N to the (massless) spring, the solar sail immediately feels the full 40N and starts accelerating at a=40N/mass. It keeps on accelerating while you keep applying the force. So the longer you hold the force on it, the faster it will move.

Your physics skills seem to be deteriorating. Why are you so reluctant to look things up? I often go and research things so I know something about what I'm saying on internet forums.