what i am trying to do is simulate a servo motor moving a object at a given acceleration rate. and then make a plot of the force needed to move the object at that acceleration rate. I have made a simple SW assembly and also made a motion study  .

I think i am not doing this the right way because. the moving object mass is 140kg and the acceleration is 1000mm per sec. and the force needed is only 140newton  (14kg) doesn't sound like enough?

Also i don't see any changes to the force when i add friction....  

Does anybody know the correct way of doing this ?