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BIO Improper lifting and the back A careful study of human anatomy allows medical researchers to use the conditions of equilibrium to estimate the internal forces that body parts exert on each other while a person lifts in a bent position (see Figure 8.19). Suppose an 800-N (180-lb) person lifts a 220-N (50-lb) barbell in a bent position. The situation can be represented with a mechanical model (Figure 8.26a). The cable (the back muscle) exerts a tension force
Rank in order the magnitudes of the torques caused by the four forces exerted on the backbone (see Figure 8.26b), with the largest torque listed first.
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