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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 2462 Views
my solution -- which is apparently wrong moondog - 10/04/2011 06:36:20 AM 2053 Views
The only thing I see which might affect your results... jh - 10/04/2011 10:58:00 AM 1786 Views
I also got 12,174 N*m. *NM* heartbreak - 10/04/2011 02:13:24 PM 698 Views
"Your answer either contains an incorrect additive numerical constant or is missing one." *NM* moondog - 10/04/2011 11:44:49 PM 25210 Views
Interesting. Did you copy/paste the problem statement for your post? *NM* heartbreak - 11/04/2011 01:49:15 AM 945 Views
here's the copy/paste from the site moondog - 11/04/2011 02:22:27 AM 1716 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 1163 Views
i had it right, it was looking for scientific notation *NM* moondog - 11/04/2011 03:00:44 AM 1141 Views
Bloody hell... *NM* heartbreak - 11/04/2011 12:53:50 PM 727 Views
You might also check... heartbreak - 10/04/2011 02:15:53 PM 1201 Views
N*m *NM* moondog - 10/04/2011 03:08:39 PM 566 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 1307 Views
it's not asking for specific sig figs moondog - 10/04/2011 09:00:23 PM 1172 Views
Are you over thinking it? L0gan - 13/04/2011 07:32:26 PM 1560 Views
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