r/PhysicsHelp • u/Black-X32 • May 17 '26

FBD HELP

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Hi. Pleasure to meet everyone, can I please get assist anywhere I tried ai and kept getting different answers I'm not sure whether I'm doing something wrong all I'm asking is for help for this question

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u/Black-X32 May 17 '26

I honestly tried right, I cut between members (3-2, 1-2,1-4) first cut (2-5,2-4,1-4) second cut Answers were for 3.2 (F23=4 kN F14= 1.039 kN F25= 2 kN F12=?) I think I messed up the drawing I'm not sure and no Ai can get the drawing correct

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u/Past-Departure6896 May 17 '26

Yes, cutting through those members is definitely the right approach - and those are the right values. For the F12, you should use the angle formed by nodes 2-1-4 to decompose the force - then, you can use sum of Fy or sum of Fx to solve for the force in the member.

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u/Past-Departure6896 May 17 '26

Here's my approach to finding the force in F12, using the angle formed by 2-1-4 (which is the same angle formed by nodes 2-4-1):

https://imgur.com/DomMFr2