1. The problem statement, all variables and given/known data Two bars masses m1 and m2 connected by a non deformed light spring at rest on a horizontal plane. The coefficient of friction b/w the blocks and the table is k. What minimum horizontal CONSTANT force F has to be applied on m1 so as to just shift m2. (For reference Problem 1.123 Irodov). 2. Relevant equations a)Fext = m*a(cm) b)M2 - M1 = Wext + Wnon-conservative where M is total mechanical energy. 3. The attempt at a solution I got the correct answer by applying the second theorem mentioned above: Supposing spring constant as a and maximum extension of spring as x and keeping our observations from the time force starts to act upto the time the block m2 first moves. ½a*x2= F*x + (-km1gx) and x = km2g/a However I find it hard to digest my own assumption that force will be minimum if the final velocity of m1 is 0. I thought a method involving forces would be easier to understand but it is too complex to work out.Would really appreciate any insight and help that gets me started on a force method.