Answer to Question #134145 in Physics for Roy Bruno

Question

The distance between two telephone poles is 50.0 m. When a 1.00-kg bird lands on the telephone wire midway between the poles, the wire sags 0.200 m.
(a) Draw a free body diagram of the bird.
Find;
(b) How much tension does the bird produce in the wire? Ignore the weight of the wire.

Answer 1

The equilibrium condition is as follows

$$2T\sin\theta=mg$$

Hence, the tension in the wire

$$T=\frac{mg}{2\sin\theta}=\rm\frac{1.00\: kg\times 9.8\: N/kg}{2\times 0.999}=4.90\: N$$