Static equilibrium: Putting it all together Lift with bent legs You injure y...

Static equilibrium: Putting it all together

Lift with bent legs You injure your back at work lifting a 420-N radiator. To understand how it happened, you model your back as a weightless beam (Figure P7.57), analogous

to the backbone of a person in a bent position when lifting an object. (a) Determine the tension force that the horizontal cable exerts on the beam (which is analogous to the force the back muscle exerts on the backbone) and the force that the wall exerts on the beam at the hinge (which is analogous to the force that a disk in the lower back exerts on the backbone). (b) Why do doctors recommend lifting objects with the legs bent?