A woman is holding a 3.6-kg sphere in her hand with the entire arm held horizontally as shown in the figure. A tensile force in the deltoid muscle prevents the arm from rotating about the shoulder joint O; this force acts at the 21° angle shown. Determine the force exerted by the deltoid muscle on the upper arm at A and the x- and y-components of the force reaction at the shoulder joint O. The mass of the upper arm is mU = 1.9 kg, the mass of the lower arm is mL = 1.1 kg, and the mass of the hand is mH = 0.4 kg; all the corresponding weights act at the locations shown in the figure.
