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t = 1 N s = 2 Your response is within 10% of the correct value. This may be due

ID: 2142023 • Letter: T

Question

t = 1           N s = 2          
Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. N The arm in the figure below weighs 37.4 N. The force of gravity acting on the arm acts through point A. Determine the magnitudes of the tension force F t in the deltoid muscle and the force F s exerted by the shoulder on the humerus (upper-arm bone) to hold the arm in the position shown.

Explanation / Answer

balancing torque about point'O'

Ft*sin(12)*0.08 = Fg* 0.29....(1)


balancing force in y- direction

Ft*sin(12) - Fs*sin(?) = Fg ......(2)


balancing force in x-direction:

Ft*cos(12) =Fs*cos(?) .......... (3)

but,

Fg=37.4 N

from equation (1)

Ft=652.07973 N............answer


from equation (2)

Fs*sin?=98.175 N...............(4)


from equation (3)

Fs*cos?=637.830 N...............(5)


from equation (4) and (5)

Fs=645.3415 N ...............answer