Seagull Mass from Tension on Telephone Wire

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Homework Statement


A seagull lands on a telephone wire midway between two poles 15 m apart. The wire (assume weightless) sags by 43 cm. If the tension in the wire is 50 N what is the mass of the seagull?

Homework Equations


Ftotal = mass x acceleration
Ftotal = F1 + F2, etc.
Fg = mass x gravity

The Attempt at a Solution



I do not even know where to start. The seagull is on a wire but I'm not sure where the force of tension lies. Is it directed to both the left and the right of the seagull? I know that Fg and the normal force cancel out I think. And what role do the distances here play? Can anyone lend me a hand?
 
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The wire and bird are in equilibrium, so Newton 1 applies. Draw a sketch. Yes, the tension acts in the rope and pulls on it both left and right and above the horizontal at an angle you can find from trig and at the given tension on both sides. The gull's weight acts down. Draw a free body digram of the bird, use Newton 1, and solve for the weight and then solve for the mass.