A typical adult man is holding his left arm at a right angle so the upper arm is

Question

A typical adult man is holding his left arm at a right angle so the upper arm is pointing straight down, and the forearm is pointing horizontally forwards. His hand is oriented palm-up. He is holding a 20 kg grocery bag by its handle in his left hand. Look up the point of attachment of relevant tendon and make sensible estimates (or look them up) for all lengths and masses. in what follows, treat the "hand plus forearm' to be one monolithic object; that is, we primarily want to understand the forces at or near the elbow.

a) Draw a free-body diagram for the hand-plus-forearm system, identifying all significant forces acting on it )including from bag handle, and don't forget the elbow joint)- the contact force from the upper arm bones.

b) Compute the magnitudes and directions of all forces, and the magnitudes and directions of all torques, taking the elbow to be axis of rotation (that is the origin or reference point). For simplicity, take the tendon direction and joint contact force both to be precisely vertical. This is NOT a bad approximation.

c) Look up the definition of mechanical advantage and compute the mechanical advantage of the grocery bag has over the tendon. why would evolution (such a brilliant designer) decide to put tendons under this kind of stress?

Explanation / Answer

Hi I have done the solution for this in my notebook. But the solution is too big , I cannot type it here because very less time is remaining.. So please rate me Lifesaver and I'll share the answer with you through email or cramster inbox. I don't do this generally, but I have no other option here because there's very less time left... you need not worry as I have the solution ready

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