1. The problem statement, all variables and given/known data 1)What should F be so that m3accelerates upwards at 1 m/s2? 2. Relevant equations F = ma 3. The attempt at a solution So I start by drawing FBD's for everything: ^^also, there is supposed to be a force of friction to the right on M1, I factored that into my solution but forgot to draw in in the diagram. Then I proceed to sum the x and y components of the forces where it is relevant. m3: ƩFy=m3a1 T-m3g=m3a1 m2: μkm2g-T=m2a1 m1: F-Nm3+μkm2g=m1a2 F=(m1+m3)(a2-1)-μkm2g i got the relationship a2=a1-1 (a2is the acceleration of the big block and a1 is the acceleration of the 2 smaller blocks) For a final answer I got: F = (m1+m3)[(μkm2g-m3g)/(m2+m3)-1]-μkm2g I am not sure if this is correct. May someone verify this solution please. In particular, I was unsure about the contact forces between the large block and the block accelerating vertically.