A cubical block of mass m and edge length a is sliding down a rough inclined plane of inclination heta at a uniform speed. Determine the torque of the normal force exerted on the block about its centre.

Step-by-step solution

Since the block is sliding down the inclined plane at a uniform speed, its net acceleration and net angular acceleration are zero. The forces acting on the block are its weight mg , the normal force N , and the frictional force f . For translational equilibrium along the inclined plane: f = mg The block is in rotational equilibrium, so the net torque about its centre of mass must be zero. The weight mg passes through the centre of mass, so its torque is zero. The frictional force f acts along the bottom surface of