Question

A 75.0 kg weight lifter is doing arm raises using a 7.50 kg weight in her hand. Her arm pivots around the elbow joint, starting 40.0 below the horizontal. (See the figure (Figure 1).) Biometric measurements have shown that both forearms and the hands together account for 5.75% of a person's weight. Since the upper arm is held vertically, the biceps muscle always acts vertically and is attached to the bones of the forearm 5.50 cm from the elbow Part A What force does the biceps muscle exert on the forearm? joint. The center of mass of this person's forearm-hand combination is 17.5 cm from the elbow joint, along the bones of the forearm, and the weight is held 38.0 cm from the elbow joint. Α φ. N F = 1 of 1 Figure Request Answer Submit - Biceps muscle Part B Elbow Januor Find the magnitude of the force that the elbow joint exerts on the forearm. 40.00 joint ? νο ΑΣφ 38.0 cm F = 7.50 kg weight Submit Request Answer

Answer 1

a)The net torque acting on arm about the point elbow joint should be zero Et=0 Fm (5.5 cos 40)-F (17.5)(cos 40) - F,(38cos 40)=0 Fom(5.5)=(0.0575)(7.5)(9.8)(17.5)+(7.5)(9.8)(38) F. (5.5)=2829.979688 F =514.5417614 N =514N b)The net force on the forearm along this direction should be zero F = 0 As there is no translation motion along vertical direction, the net force on the forearm along this direction should be zero F = 0 -F, +F3-FX-FX0 F, = Fm - Fx - F = 514 - (0.0575)(75)(9.8)-(7.5)(9.8) = 419.36875 = 420 N c)The direction is downwards d)decreases

Answer 2

the answer to d is stay the same, whoever answered this question does not know what they are talking about and should not answer questions