Figure 1. Free body diagram of the back model. T is the tension exerted by the extensor muscles (all muscles combined), Wb is the weight of the upper body (torso and arms), W is the weight of the object held in the hand. LT is the perpendicular moment arm of T; Lb and Lw are the perpendicular moment arms of Wb and W. Question 3: The free body diagram of the back model in static equilibrium is shown in Figure 1 above. Develop an equation for T as a function of W in terms of the dened variables. Hint: take a moment about the lower back where Fx and Fy act (is. lower lumbar spine). Please show your work