- #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

Σ

*t*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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