The bones of the forearm (radius and ulna) are hinged to the humerus at the elbow. The biceps muscle connects to the bones of the forearm about 2 cm beyond the joint, forming a second-class lever. Assume the forearm is 2 kg in mass and 0.4 m long. The humerus and biceps are (nearly) vertical and the forearm is horizontal. The hand holds a mass A of 1.5 kg. The arm and mass are in static equilibrium. (Use g = 10 m/s2.)
What is the magnitude of the torque of the weight of the forearm about the elbow?