A block of mass 3 kg is pressed against a rough vertical wall by a horizontal force of 100 N . The coefficient of static friction between the block and the wall is 0.5 . If g = 10 m s ⁻² , what is the magnitude of the frictional force exerted by the wall on the block?

Step-by-step solution

The normal force N exerted by the wall on the block is equal to the applied horizontal force. N = 100 N The maximum possible static friction (limiting friction) is: f_ s, max = _s N = 0.5 100 N = 50 N The downward force acting on the block due to gravity is: mg = 3 kg 10 m s ⁻² = 30 N Since the required force to hold the block in equilibrium ( 30 N ) is less than the maximum static friction ( 50 N ), the block does not slip. Static friction is a self-adjusting force and will exactly balance the downward weight. The