Physics 1028 Study Guide - Final Guide: Net Force, Abscissa And Ordinate, Mechanical Equilibrium
Document Summary
Only a part of the person"s body is the object of interest in this problem: we consider the combination of head, trunk and both arms, while the legs are excluded as they are wedged under the restraint pad. This means that the person tries to lift the upper body, not the entire body by pulling on the handle. We consider four forces in this case: the weight of the upper body, the two forces exerted by the handle on the hands and a contact force between the upper and the lower body of the person. This latter force is neglected because we consider a person who intends to pull but at the instant discussed in the problem only hangs on the handle. We combine the remaining forces in the shown free body diagram. We choose the direction upward as the positive axis and assume that the same force f acts at each hand.
