Model the upper arm, the forearm, and the hand as separate body segments. Assume the following body segment masses:
Upper arm: 2.24 kg
Forearm: 1.28 kg
Hand: 0.48 kg
Assume that the center of masses of the upper arm and the forearm acts in the geometric center of the respective body segment, and the center of mass of the hand acts at the same location that the cable is in the hand (given below). If the person is performing a left arm exercise with a 20 lb weight attached to a cable that wraps around a pulley attached to the ceiling, what are the reaction forces and torques at the shoulder, elbow, and wrist joints if the points below are known? State your results in SI units, and use a coordinate system with the positive x-direction pointed forward, the positive y-direction pointed upward, and the positive z -direction pointed to the right side of the body.
a. Shoulder joint: (0,0,0)
b. Elbow joint: (10cm, -15cm, -28cm)
c. Wrist joint: (21cm, 14 cm, -23cm)
d. Point where cable is in the hand: (24cm, 20cm, -19cm)
e. Cable is attached to pulley at (14 cm, 30 cm, -1cm)
f. The weight hangs directly below the pulley.