Question

Draw a FBD of a person who is holding a 9 pound weight in her hand. Her shoulder is abducted to 90^o, her forearm is fully extended and her wrist is at neutral. The weight of her upper extremity (UE) is 11.1 pounds. The center of gravity of the 9 pound weight is 22.5 inches from the axis of rotation. The center of gravity of her UE is 8.75 inches distal to the axis of rotation. The deltoid muscle, which is attached 4.8 inches distal to the axis of rotation, is providing the force to maintain the abducted position of the UE.

a. Calculate the torque of gravity. Show all your work. In your drawing, which direction (+ or -) is the torque of gravity acting?

Answer 1