B M Sharma Solutions for Chapter: Elasticity, Exercise 4: CONCEPT APPLICATION EXERCISE

Assuming Young's modulus of aluminium to be $7\times {10}^{10} \mathrm{N} {\mathrm{m}}^{-2}$, find energy stored in an aluminium rod of cross-section ${10}^{-4}{ \mathrm{m}}^2$ and $0.1 \mathrm{m}$ long when compressed by a load of $10 \mathrm{kg}$.

The work done it stretching a wire by $0.1 \mathrm{mm}$ is $4 \mathrm{J}$. find the work done in stretching another wire of same material, but with double the radius and half the length by $0.1 \mathrm{mm}$ in joules.

A block of mass $M$ is suspended from a wire of length $L$ , area of cross section $A$ and young’s modulus $Y$ . Find the elastic potential energy stored in the wire.

A $40 \mathrm{kg}$ boy whose leg bones are $4{ \mathrm{cm}}^2$ in area and $50 \mathrm{cm}$ long falls through a height of $2 \mathrm{m}$ without breaking his leg bones. If the bones can stand a stress of $0.9\times {10}^8 \mathrm{N}/{\mathrm{m}}^2$, calculate (i) $Y$ for the material of the bone and (ii) $k$ (force constant).

Identical springs of steel and copper are stretches by equal lengths. On which is more work done?

Identical springs of steel and copper are stretched by equal forces, $F$ each. On which is more work done.