Second part asks: a 7.00kg block is stacked on top of the 5.20 kg block. What is the magnitude F of the force acting horizontally on the 5.20 leg block as before, that is required to make the 2 blocks start to move together?

Required information A 5.20-kg block is at rest on a horizontal floor. If you push horizontally on the 5.20-kg block with a force of 12.0 N, it just starts to move. What is the coefficient of static friction? Numeric Response