# Equilibrium and tension problem

1. Nov 4, 2004

### FarazAli

The problem as stated in the book
"Calculate the tension $$F_{t}$$ in the wire that supports the 30-kg beam shown in fig. 9-57 (attached), and the force $$F_{w}$$ exerted by the wall on the beam (give magnitude and direction)."

Getting the Tension in the string was easy.
$$\sum\tau = F_{ty} \cdot x_{1} - mg(\frac{x_{1}}{2}) = 0$$
$$F_{ty} = 147N$$
$$F_{t} = \frac{F_{ty}}{sin 50} = 1.9 \times 10^2N$$

To get the $$F_{w}$$, I used the sum of forces.
$$\sum{F_{x}} = F_{tx} - F_{wx} = 0 \Rightarrow F_{tx} = F_{wx} = F_{t} \cdot cos 50 = 123.35 N$$
$$\sum{F_{y}} = F_{ty} + F_{wy} - mg \Rightarrow F_{wy} = mg - F_{ty} = 102.11 N$$

So now I have the two components for $$F_{w}$$ , I use pythagorous and solve for the resultant vector to get 160.13 N. The book, however, says the answer is $$1.9 \times 10^2 N$$. Can anyone tell me what I'm doing wrong?

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2. Nov 4, 2004

### FarazAli

nevermind, the problem was when I confused $$F_{wy}$$ for $$F_{w}$$

Last edited: Nov 4, 2004