- #1
NoobeAtPhysics
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Homework Statement
The truss is suspended by two pin joints. Each segment is 3 m wide and 4 m high. The applied force is F = 1 N. What is the force in member 2?
Homework Equations
Sum of force = 0
The Attempt at a Solution
Using method of sections (to get force at 3), so taking the right portion
I am trying to understand the sum of the force in the y direction of the section.
sum of force y of portion =0 =-1 - J_3 cos(180-arctan(3/4))
My question, do we use 180-angle when looking at the angle,
also is it negative J_3, since the J_3 is pointing downwards?
I already know that the answer is 1N, I just don't understand this part.
Thank you.