1. The problem statement, all variables and given/known data • If we add a third block, leaving the 10 N force the same, what happens to f3, the net force on the 3 kg block? A. Increase B. Decrease C. Stay the Same D. Not Enough Info. 2. Relevant equations F net = m * a 3. The attempt at a solution Ignore the colors in the attachment. All that matters are the numbers. The acceleration of the system with only the two blocks is 1.25 m/s^2. 10 N = (3 kg + 5 kg) * a a = 1.25 m/s^2 The acceleration of the system with the three blocks is now 0.625 m/s^2. I'm trying to set up an equation to solve for the net force on the 3 kg block. 10 N + Force of block 3 on block 5 - Force of block 5 on block 3 = ...? IF that's a correct equation.