Do "torques" (on a bar) work the same way as "weighted averages"?
Von: ship (shiphen@gmail.com) [Profil]
Datum: 19.12.2008 14:43
Message-ID: <fc2a8547-e5c5-425a-a994-999318e9649b@k1g2000prb.googlegroups.com>
Newsgroup: uk.education.mathsalt.engineering alt.mechanical.engineering
Datum: 19.12.2008 14:43
Message-ID: <fc2a8547-e5c5-425a-a994-999318e9649b@k1g2000prb.googlegroups.com>
Newsgroup: uk.education.mathsalt.engineering alt.mechanical.engineering
"Torques" (on a bar) vs. "weighted averages" For example, suppose that I have a solid, horizontal bar that is 10 units long. And suppose that the bar is pivoting about a point half way along the length of the bar. Now suppose there is a mixed/'random' collection of weights sitting on the bar at different points along the bar. Now if some of the weights are on opposite sides of the pivot, it is clear that to some extent they would cancel each other out and, if I am correct, whatever is left over would form a rotational "torque". From my O-level physics I recall "torque" is basically "force x distance". So I presume that if you just added up all of the individual torques on one side of the bar, and subtracted it from all of the torques on the other side of the bar, that whatever would be left over would be would be the resulting torque that the bar would exert on any objectthat tried to stop it from rotating. (Am I right so far?). But my question is this: Would this resulting torque mathematically be the SAME THING as if you took a "weighted average" of all the torques? [And if not, is there anything simple one could do with mechanical levers etc to visualise what the heck a "weighted average" actually means in mechanical terms?] Ship Shiperton Henethe P.S. One issue that concerns me is that if there is a huge weight placed at the very middle of the bar (i.e. immediately above the pivot point) it obviously doesnt affect the bar's torque (because force x zero is stil zero!) But would a "weighted average" be affected by a large weight in the middle of the bar.[ Auf dieses Posting antworten ]
