Question
A rigid bar of mass 15 kg is supported symmetrically by three wires each 2.0 m long. Those at each end are of copper and the middle one is of iron. Determine the ratio of their diameters if each is to have the same tension.
Solution
Tension force acting on each wire is the same. Hence, the extension is the same for each wire.
Since, the wires are of the same length, the strain will also be same.
Young's modulus is given by,
