Determine the force in each member of the loaded truss. The force is positive if in tension, negative if in compression.
I have attached an image of the problem
The Attempt at a Solution
I defined the positive y axis to be from B to A and hence the positive x axis is from B to C.
To find AB I took the sum of the force in the y-direction on point B, my calculations are:
0 = AB - (224kg)(9.8)cos(37)
AB = 1753.2 N
This answer is correct.
Then to find BC I found the forces in the x-direction at point B
0 = -BC + (224)(9.8)sin(37)
BC = 1321.1 N
However it says my answer is wrong. I suspect that it should be -1321.1 N but I have not tried this.
I am stuck on finding AC.
Some of the my classmates tried:
(BC)cos(37) which gives me 1055 N but it says this is wrong.
Any help would be appraciated.