Statics Question Moment for a Truss

  • #1
baird.lindsay
36
0

Homework Statement



I need to find the moment about G. Please ignore the question in the image.

http://img13.imageshack.us/img13/6086/4cv0.jpg [Broken]

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Homework Equations



r X F

The Attempt at a Solution



Moment about G = -(30*800) + (-300*50) + 60 A + 17.32*500 + (-17.32*500(4/5)) =0

I keep getting A= 621 N but my solution is saying 721N. I am doing something wrong, not sure what.
 
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Answers and Replies

  • #2
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
12,809
1,670
You need to look at the moment produced by both components for the 500 lb load at point I.

The reaction at A should be in lbs rather than newtons.
 
  • #3
baird.lindsay
36
0
Moment about G = -(30*800) + (-300*50) + 60 A + 17.32*500 + (-17.32*500(4/5)) + (-40*500(3/5)) =0

When I do that I get 821lb? I am still off....
 
  • #4
baird.lindsay
36
0
wrong way its 20 thank you!!
 

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