Question Details	Asked By	Asked On
this is a big problem for me (biology)	izwan	09/28/07
A person carrying a heavy bag normally finds the impact of the weight differently if he carries it in different ways. For example if he carries it by the handle or by a strap on the shoulder or putting the whole bag on top of his shoulder. Why is this so (as the weight of the bag is the same in all the cases)?
Answered By		Answered On
graeylin		09/28/07
yup, Jim has it answered. It all has to do with the center(line) of gravity...the further you place a weight away from the mid structural support, the more energy is needed to support it. since most of your strength in lifting comes from the area of your pelvis and spine, along the line from your ankle/knees through your shoulders, the closer you get to that line, the "easier" it seems to be to carry a given weight. the further you go, the harder, because the body has to expend energy to "brace" or support the muscles and bone structure hanging out "away" from the center. If you could counterbalance the weight, it wouldn't matter, but you can't really carry a gallon on the left side and a gallon on the right, because your arms aren't connected firmly to allow the counterbalance to work.

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