# Determing the Force in Each Member of the Loaded Truss

## Homework Statement

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

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.

#### Attachments

• statics hwk 13 4.002.png
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I have gotten the answer now.

BC = -1321.1 N

AC = BCcos(53) = 795.05 N but I don't understand why these are correct.

PhanthomJay