Two indentical uniform rods each of mass `60kg` are hinged from the lowest points, and their upper ends are connected by a light wire of mass `0.01kg` and length `1m`. The system is in equilibrium such that the wire is always horizontal. A strong wind is blowing which causes the wire to vibrate in its `3^(rd)` ovetone. The frequency of the sound produced by the wire is:

Options

A. `100Hz`
B. `200Hz`
C. `300Hz`
D. `400Hz`

Answer

D

Explanation

Applying torque balance on one rod
`(mg)(l/2)sin(53^(@))=(T)(l)sin(37^(@))impliesT=2/3mg`
`implies` Frequency of the wire
`4/(2l)sqrt(T/(mu))=4/(2xx1)sqrt((2/3xx60xx10)/(0.01))=400Hz`