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Free body diagram help

  1. Sep 11, 2016 #1
    1. The problem statement, all variables and given/known data
    upload_2016-9-11_2-30-0.png

    2. Relevant equations


    3. The attempt at a solution
    I got the components of each force. I called the Force from BA "B" and the force from CA "C" and then the force going downward on D "W"

    FBy=sin30*B
    FBx=-cos30*B

    FCy=3/5*C
    FCx=4/5*C

    W=-500
    ~~~~~~
    ΣFx= -B*cos30 + 4/5C = 0
    ΣFy= B*sin30 + 3/5C - 500 = 0

    -0.866*B +0.8C=0
    0.5*B+0.6C=500

    Now when I solve the system of equations by elimination I'm getting B=434 and C=470 (I even checked on a calculator) , but the back of the book says 478 for B and 518 for C


    What am I doing wrong?

    I know this is kind of a dumb question like it's basic precalc but I've done it so many times over and over again I don't know what im going wrong
     
  2. jcsd
  3. Sep 11, 2016 #2
    You make a careless mistake with the weight of the crate. It is not 500, check again and you will get the correct answer =)
     
  4. Sep 11, 2016 #3
    jvhgvhgvhgvhjsd TRUE <3 thank you
     
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