Unformatted text preview: at what angle relative to horizontal should the force be applied so that it can have the smallest magnitude needed to raise the wheel over the curb? Please illustrate your answer with a carefully drawn diagram. 1. [Lifting] A person bends over and lifts a 50 lb object with their back in the horizontal position (a terrible way to lift something!. ..and we'll see why in this problem). The back muscle, attached at a point twothirds up the spine from the hip pivot, maintains the position of the back, and the angle between the spine and this muscle is 12°. Using the simplified mechanical model in the diagram on the right and taking the weight of the upper body to be 80 lb, find (a) the tension in the back muscle and (b) the compression in the spine. (c) How do these forces compare with the weights of the object and the upper body?...
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 Fall '07
 LECLAIR,A
 mechanics, Force, Work, Pickup truck, normal contact forces, carefully drawn diagram

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