Your friend Joe hangs from a horizontal bar by his two hands,with his arms each inclined 35 degrees from the vertical (so that his arms have an angle between them of 70 degrees.If his mass is 76 kg,what is the tension in each of his arms?
A)745 N
B)372 N
C)455 N
D)909 N
E)1090 N

Question

Quizplus · Accepted Answer

First, we need to draw a free-body diagram for Joe. The forces acting on him are the tension in each arm (T), his weight (m*g), and the normal force from the bar (N) which is perpendicular to his arms.

Next, we need to resolve forces horizontally and vertically. There is no horizontal acceleration, so we can set the horizontal forces to zero. Vertically, because Joe is not accelerating, we know that the net vertical force is zero. Therefore, we have:

Vertical forces: N - m*g - T*sin(35) - T*sin(35) = 0

Simplifying and solving for T, we get:

T = (m*g)/(2*sin(35)) = (76*9.8)/(2*sin(35)) = 454.6 N

Rounding to the nearest whole number, the answer is C) 455 N.

Your Friend Joe Hangs from a Horizontal Bar by His