Question

A torque of 300 N-m acts on the brake drum shown in Fig.(a). If the brake band is in contact with the brake drum through 250° and the coefficient of friction is 0.3 determine the force P applied at the end of the brake lever for the position shown in the figure.

Answer 1

Figure (b) shows free body diagrams of brake drum and the lever arm.

Consider the lever arm. Taking moment about the hinge, we get 

T₂ × 50 = P × 300 

P = 274.0 N.