- #1
ryley
- 20
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Homework Statement
In figure 12-34, a uniform beam of weight 500N and length 3m is suspended horizontally, on the left it is hinged to the wall and on the right end of the beam is a cable attached to support it. the cable is attached distance D up the wall from the hinge. The least amount of tension that will snap the cable of 1200N.
a) What is the value of D that corresponds to that tension?
Homework Equations
Σt net=0
The Attempt at a Solution
I've figured out to use the torque net equation to find the angle of θ and then solve for the distance D. What I'm not understanding is why I can't just use the Fnet y=0 to solve for θ?
Fnety=Tsinθ- mg
θ=arcsin(mg/T)
Doing it this way yields a different result than if I solve for θ using this method
t net z= mgr⊥-Tsinθr⊥
I understand just seeing how the numbers are different that it will change the answer but I don't understand why I can use the force net y to solve for θ and then use that to solve for the length of D.
Thanks for the help!
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