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The only thing I see which might affect your results... jh Send a noteboard - 10/04/2011 10:58:00 AM
Tb = Torque of beam

Tp = Torque of person

T = total torque

T = Tb + Tp

Tb = (580kg) * (9.8m/s^2) * (1.7m) = 9662.8Nm

Tp = (75kg) * (9.8m/s^2) * (3.40m) = 2499Nm

T = 9662.8 + 2499 = 12161.8Nm

edit: i know this is wrong because it is from an online homework sheet which automatically tells you whether or not your answer is correct. even rounding to 3 significant figures with the above answer was not taken as correct.


Is the fact that you use 9.8 instead of the standard average of 9.81, but the error involved is not all that great... it could give you a difference in the third figure, though. It is a bit tricky to use g, since it varies a bit depending on your location.

But you are using the standard definitions of torque, F*l, and torques applied to the same point should be additive, so nothing wrong there. Everything seems to be at right angles, so trigonometry is not needed...

try 12174Nm instead. Could be a rounding problem, of course, and then nothing we do is relevant. :P
"People think it must be fun to be a super genius, but they don't realize how hard it is to put up with all the idiots in the world" - Calvin.
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got a physics homework problem, who can help me out? moondog - 10/04/2011 06:33:44 AM 2314 Views
my solution -- which is apparently wrong moondog - 10/04/2011 06:36:20 AM 1892 Views
The only thing I see which might affect your results... jh - 10/04/2011 10:58:00 AM 1570 Views
I also got 12,174 N*m. *NM* heartbreak - 10/04/2011 02:13:24 PM 615 Views
"Your answer either contains an incorrect additive numerical constant or is missing one." *NM* moondog - 10/04/2011 11:44:49 PM 25085 Views
Interesting. Did you copy/paste the problem statement for your post? *NM* heartbreak - 11/04/2011 01:49:15 AM 867 Views
here's the copy/paste from the site moondog - 11/04/2011 02:22:27 AM 1564 Views
You summed it up well enough. I'm out of ideas. Sorry. If you find out the answer.... heartbreak - 11/04/2011 02:50:50 AM 1000 Views
i had it right, it was looking for scientific notation *NM* moondog - 11/04/2011 03:00:44 AM 1059 Views
Bloody hell... *NM* heartbreak - 11/04/2011 12:53:50 PM 642 Views
You might also check... heartbreak - 10/04/2011 02:15:53 PM 1045 Views
N*m *NM* moondog - 10/04/2011 03:08:39 PM 496 Views
If this thing works at all like Webassign (an online homework thingy I used to do)... Aemon - 10/04/2011 08:28:03 PM 1122 Views
it's not asking for specific sig figs moondog - 10/04/2011 09:00:23 PM 1010 Views
Are you over thinking it? L0gan - 13/04/2011 07:32:26 PM 1253 Views
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