- #1
sukibelle
- 10
- 0
Homework Statement
Determine shear force at point D of Beam
http://tinypic.com/r/339m5b6/7
Homework Equations
Sign conventions for cut at d when considering LHSFBD
M = xFy - yFx - cross product...
The Attempt at a Solution
I've found the reaction forces by finding the sum of moments about A (the pin).. Ay and By reaction forces are 9 Kn up..
then i went to find shear force by taking a cut across D and considering the LHS FBD..
I took the moments about A and my answer was really wrong, whereas when I took the sum of the Forces in the Y direction I got the right answer. I want to know why this working out is wrong.. For sum of moments about A.. or why I shouldn't be taking the moments about A?
-2(6)/3*(2*6/9)*(6/2) - 6*(VD) = 0
Here is my FBD for it also
http://tinypic.com/r/2pskdhj/7 (just realized that 3 should be a 9)... The Answer is V = 5 .. i do not get that :(