**Elasticity, Hooke’s law and elastic constants of isotropic solids and their inter-relation;**

Questions:

**Q 1.** A rubber cord 1mm in diameter and 1 m long is fixed at one end and a weight of 1 kg is attached to the other end. If they Young’s modulus of rubber is $0.05 × 10^{11} cm^{-2}$, then find the period of the vertical oscillations of the weight . **[10 marks]**

**Q 2. **A light rod of length 100 cm is suspended from the ceiling, horizontally means of two vertical wires of equal length tied to its end. One of the wire is made of steel and its cross section is 0.5 sq.cm and the other is of brass of cross section 0.1 sq.cm. find the position long the rod at which a weight may be hung to produce (i) equal stress in both the wires (ii) equal strain in both the wires. **[15 marks]**

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