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# Maths Moments help #2 watch

1. OA is uniform, OA is a porch roof, BA is the chain. It is hinged at O. Find the tension in the chain in terms of W. when angle between OA is 60 degrees. I know the Answer but dont know how to get to it.

Attachment 699176
2. (Original post by joyoustele)
OA is uniform, OA is a porch roof, BA is the chain. It is hinged at O. Find the tension in the chain in terms of W.
Label some forces.
3. (Original post by RDKGames)
Label some forces.
the only information i have is. angle between OA is 60 and weight.
4. (Original post by joyoustele)
OA is uniform, OA is a porch roof, BA is the chain. It is hinged at O. Find the tension in the chain in terms of W. when angle between OA is 60 degrees. I know the Answer but dont know how to get to it.

Attachment 699176
Have you spotted that you have an equilateral triangle?
5. (Original post by tiny hobbit)
Have you spotted that you have an equilateral triangle?
yes. I just dont know how to go about finding the tension
6. Never mind guys. I think i found a way.
7. (Original post by joyoustele)
OA is uniform, OA is a porch roof, BA is the chain. It is hinged at O. Find the tension in the chain in terms of W. when angle between OA is 60 degrees. I know the Answer but dont know how to get to it.

Attachment 699176
Hi, for future questions you really need to post your diagram and show us your working. Otherwise we have no way of knowing where you're stuck
8. (Original post by Notnek)
Hi, for future questions you really need to post your diagram and show us your working. Otherwise we have no way of knowing where you're stuck
okay.
9. RDKGames Notnek tiny hobbit

Sorry for the lack of detail in the question above. I didnt understand the concept of solving for the tension in the chain. I just read on how to solve it. However i'm a bit confused on one particular bit.

when they were finding the moment of W, about the hinge (Black dot) they used 2cos30. instead of 2sin60.I know both ways work, but can any of you explain why they used 2cos30?
10. (Original post by joyoustele)
RDKGames Notnek tiny hobbit

Sorry for the lack of detail in the question above. I didnt understand the concept of solving for the tension in the chain. I just read on how to solve it. However i'm a bit confused on one particular bit.

when they were finding the moment of W, about the hinge (Black dot) they used 2cos30. instead of 2sin60.I know both ways work, but can any of you explain why they used 2cos30?
Personal choice. Maybe due to that being the horizontal force when you draw a triangle on there with angle 30, and then the W there is already a drawn side.

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