Question

In the movie Terminator, Arnold Schwarzenegger lifts someone up by the neck and, with both arms fully extended and horizontal, holds the person off the ground. If the person being held weighs 610.0 N, is 60 cm from the shoulder joint, and Arnold has an anatomy analogous to that in the figure below, what force must each of the deltoid muscles exert to perform this task? [Hint: The weight of the arm is 30.0 N and its center of gravity is at the elbow joint, 27.5 cm from the shoulder joint.] kN

Axis Scapula Deltoid muscle 12 cm 27.5 cm. Humerus

Answer 1

Resolving the force exerted by the deltoid muscle F into two perpendicular components the vertical component will be F sin15 Generally the weight of the arm of a person will be nearly 30N Now applying the equilibrium condition (12cm)(F sin15) (27.5cm) (30N+(60cm) (305N) 3.10F825+18300 19125 3.10 6169