Originally Posted By: paul
NO !!!!

Yes. It's your design. You specified 3900N. That requires 2s, and 78m. If you want a shorter turnaround then you need to choose a higher force to get the job done faster. The value of this force is arbitrary, it doesn't change the outcome. That might sound strange, but any change in the force has to be compensated for by applying it for a different length of time so you end up with the same change in momentum.


Im not sure why your so concerned with time as the time is given in the acceleration of the mass.

Have a free floating stationary block of 1kg. Push it with 10N for 1s. Then run round the other side and push it in the opposite direction with 10N for 1 hour. The block ends up stationary of course, because the two opposite forces balance, right?


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

As I said before, there's no point going into other details unless you understand what that factor of 2 is for. Without it, the machine will indeed fly. Why don't you try to understand it? Don't have to listen to me, go check google or ask someone else. Or just look at this:
Answer to a physics problem.

Edited by kallog (06/22/10 01:00 PM)