- #1

- 204

- 0

## Homework Statement

Ok, you'll have to wait for my picture. Basically we are doing trusses, and I'm not sure where I'm going wrong here.

We are to find the tension/compression in each member(line) of the truss.

Ok, from my picture. F1 is directly at B(in neg y direction), and is 2800N. F2 is at point D(in the neg x direction) and is 2100N.

The distances between A&B, and B&C are 4m. A is a pin system(basically has x and y forces).....and C is held up by a cable(I believe only supports in the y direction).

I also drew another picture, which consists of little circles on each joint, and arrows pointing in the directions of the tensions(and forces acting on the "circles").

## Homework Equations

## The Attempt at a Solution

Ok, I'm only going to post some of this, to see if I started correctly(where I think I messed up).

So, from my picture, I took overall equilibrium. So, I chose to sum moments about point A=0(with a counter-clockwise rotation I chose).

moments at pt A = 0= 8Cy -2800(4) - 2100(3.4641)

Cy = 1259.33N up

Sum Forces in +x direction=0

Ax - 2100 = Ax=2100N to the right

Sum forces in +y direction = 0

Ay + Cy - 2800 = Ay = 1540.67N up

If this is correct, then I'll post more. Next, I drew that other picture, and started at points and found the tension(as I draw them all in tension to begin with) at each point.

Thanks,

Brad

View attachment problem 6.bmp