Internal Forces on a Truss (Again)

[smrgn92]

Homework Statement

Hello, in the attached file shows a picture of the problem I need to resolve. The question asks to calculate the internal force in the member BC. There is a pin support located at joint A and D, which is not shown in my diagram, and it is also symmetrical, which makes things slightly easier.

Homework Equations

See attached file.

The Attempt at a Solution

I calculated the forces in the y direction using the equilibrium equation, and then calculated the angle between member AE and AB using basic trigonometry to be 26.57 degrees. I then resolved the internal forces in members AE and AB. However, I am unable to determine what else I can do with resolving further internal forces in this structure. For all other joints, there are at least 2 unknown forces, for which I am unable to determine any other internal forces. What should be my next approach? Thanks, forum.

 

[SammyS]

Homework Statement

Hello, in the attached file shows a picture of the problem I need to resolve. The question asks to calculate the internal force in the member BC. There is a pin support located at joint A and D, which is not shown in my diagram, and it is also symmetrical, which makes things slightly easier.

Homework Equations

See attached file.

The Attempt at a Solution

I calculated the forces in the y direction using the equilibrium equation, and then calculated the angle between member AE and AB using basic trigonometry to be 26.57 degrees. I then resolved the internal forces in members AE and AB. However, I am unable to determine what else I can do with resolving further internal forces in this structure. For all other joints, there are at least 2 unknown forces, for which I am unable to determine any other internal forces. What should be my next approach? Thanks, forum.

You have an error in getting F_AB.

You changed the cosine back into the sine .Also, can you clarify?
Is member EB perpendicular to member AG ?

 

[smrgn92]

Thank you, silly mistake there. And I'm not entirely sure, the question doesn't specify, but I'm assuming it is.