Help solving this question would be appreciated: As a short person at 5'3'' with short arms, I find it challenging to lift furniture with a taller person, because they always naturally lift the object higher than I can. I got into a debate with my partner about this because we were lifting a large, heavy and long chest of drawers together. He stands at 6 ft., and was holding the object about 6 inches higher than me, and I was lifting at the maximum height I could. I said, "lower your end so there is less weight on me." and he continued to say that the amount of weight put on my end from the "small amount of height difference" was negligible and probably only added a few ounces of weight on my end. From my perspective, it was more like 20-30 lbs. alleviated when he held his end level with mine. My question is, could a small amount of unlevel of a large object, put a lot of weight on the lower end? Or does it have to tilt a bit more, as in going down a set of stairs to become noticeable? I would estimate the chest weighing about 80lbs. Thanks!
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It is easier if we suppose a frictionless object like a big ice bar. The grip of a common object has some friction component, but with that simplified model the concept is more clear.
The forces of each one can be split in perpendicular and parallel to the bar. Of course the higher grip has only the perpendicular component.
Making a diagram of forces and moment, it is possible to find the forces as a function of the angle $\theta$ and the weight $w$.
Claudio Saspinski
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