1. The problem statement, all variables and given/known data Block A weighs 4 N and block B weighs 8N. The coefficient of sliding friction between all surfaces is 0.25. Find the force P necessary to drag block B to the left at a constant speed if A) if A rests on B and moves with it B) if A is held at rest C) if A and B are connected by a light flexible cord passing around a fixed frictionless pulley. 3. The attempt at a solution I have drawn the free body diagrams. A) Ff=coefficient x Fn = .25 (8 + 4) = 3 Is that right? B) I know the fsB = (8 + 4) coefficient of static friction fsA = coefficient of static friction (4) I also know that these have to be equal in order to move. So... fsA = fsB But where do I put the P? On the A side or the B side? C) I know that P must be equal to all the forces in the x-direction in order for the block to move. The sum of the forces in the x-direction = T + fsA + fsB so... P = T + fsB + fsA and P = T + (.25)(4) + (.25)(12) P = T + 4 How do I find T? I know that the sum of all the forces = ma And the acceleration in this case is 0. But 0 = T + 4 would give T= -4. And P =0. I don't think that can be right.