Methods of Section: Truss problem

[SagarPatil]

1. The problem statement,
Have to find the forces in AC & BC using the methods of section.

all variables and given/known data
Distance
AB = 79cm
BC = 63
AC = 98
d = 3.833
AZ = 62.881
ZC = 75.16

Point B is a roller and point A is a Pin

Whats given is 39.94N Forces @ C going down

Homework Equations

ΣFx
ΣFy
ΣMa

The Attempt at a Solution

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[insightful]

You appear to have cut through BC and AC, and are analyzing the part with point C.
Your reaction forces at the wall appear to be correct.
I suggest analyzing the part next to the wall.

 

[SagarPatil]

You appear to have cut through BC and AC, and are analyzing the part with point C.
Your reaction forces at the wall appear to be correct.
I suggest analyzing the part next to the wall.

If I take moment at point A does Bx cancel ?
BC I calculated is correct?

 

[insightful]

If I take moment at point A does Bx cancel ?
BC I calculated is correct?

You have BC=Bx, which cannot be. If I read your drawing right, Bx=31.79 (I agree) and taking the moments around A of the section next to the wall tells you this must cancel the horizontal component of BC.

 

[SagarPatil]

You have BC=Bx, which cannot be. If I read your drawing right, Bx=31.79 (I agree) and taking the moments around A of the section next to the wall tells you this must cancel the horizontal component of BC.

I got the answer. I didn't understand the concept first. After reading I got it :D