Quote:
This means the -3900N force was applied for 2 seconds.


NO !!!!

the mass has a final velocity of 39.038 m/s when it enters the turnaround after being accelerated.

the turnaround would have to have a lenght of
39.038 meters * 2 = 78.076 meters
for the mass to consume 2 entire seconds while passing through it.

so your wrong.

Quote:
It's meaningless to add up forces while ignoring the times they're applied for. I'll include time below...


and its even less meaningless to include erroneous times , Im not sure why your so concerned with time as the time is given in the acceleration of the mass.

ie...5 meters / SECOND / SECOND...

meaning each second..

Quote:
Maybe it's travelling a longer and longer distance each cycle too, or maybe it isn't. Havn't worked that out.


maybe that is where your insertion of 2 seconds will come in !!!

LOL.

3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science.