A block of mass m is pressed against a rough vertical wall by applying a constant horizontal force F . If the block slides downwards along the wall with a constant velocity, the magnitude of the total contact force exerted by the wall on the block is :

Step-by-step solution

Since the block moves with a constant velocity, its acceleration is zero, and the net force acting on it must be zero. In the horizontal direction, the normal force N exerted by the wall balances the applied force F . Thus, N = F . In the vertical direction, the upward kinetic friction f balances the downward weight of the block. Thus, f = mg . The total contact force exerted by the wall is the vector sum of the normal force and the frictional force. Since they are perpendicular to each other, its magnitude is: F_