Solve Prob. 8.90 assuming that the normal force per unit area between the pad and the surface

Question:

Solve Prob. 8.90 assuming that the normal force per unit area between the pad and the surface varies linearly from a maximum at the center to zero at the circumference of the pad. Problem 8.90: A 7-in.-diameter buffer weighs 10.1 lb. The coefficient of kinetic friction between the buffing pad and the surface being polished is 0.60. Assuming that the normal force per unit area between the pad and the surface is uniformly distributed, determine the magnitude Q of the horizontal forces required to prevent motion of the buffer.

S in.