Hey everyone. First time poster here.(adsbygoogle = window.adsbygoogle || []).push({});

I was helping a friend do some Statics homework (I completed the course last Fall), and I ran into a really unsettling problem.

I have done this problem over several times with the same result.

When I do the problem only summing forces in the X and then Y direction, I get an answer that "checks out."

When I do the same problem, but FIRST solve for tension using sum of moments about point R, I get a result for tension that does NOT check out.

I have tried doing this with simple algebra methods, and using cross products to determine the magnitude of tension. EVERY TIME I USE MOMENTS I get the same answer.

Here's the problem:

http://img829.imageshack.us/img829/3564/stuffcw.png [Broken]

I just sketched this up. R is just a reaction force. In the actual problem it's a rocker end that is butted up against a floor and a wall. Tension is a wire that is connected to the same wall.

When I sum forces in X and then Y, I get

T = 167.2 N

R = 192.9 N

When I sum moments I get

T = 83.56 N

then sum moments in Y direction gives me R = 96.42

Just looking for anyone to try to figure it out with moments and see if they can get it to work.

Thanks,

Luke

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# Statics problem, determinate without moments, indeterminate with?

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