The board which weighs 86.5N is sandwiched between two other boards. If the coefficient of friction between the boards is 0.544, what must be the magnitude of the horizontal forces acting on both sides of the center board to keep it from slipping downward? 2. Force of friction = coefficient x Normal force Normal force = mg 3. I first found out what the normal force is by multiplying 86.5 by 9.8 = 847.7. Do I then find the horizontal forces by multiplying that value by the coefficient? Thank you so much.