The uniform 72-ft mast weighs 600 lb and is hinged at its lower end to a fixed

Question:

The uniform 72-ft mast weighs 600 lb and is hinged at its lower end to a fixed support at O. If the winch C develops a starting torque of 900 lb-ft, calculate the total force supported by the pin at O as the mast begins to lift off its support at B. Also fi nd the corresponding angular acceleration a of the mast. The cable at A is horizontal, and the mass of the pulleys and winch is negligible.