A metal wire of length $L_1$ and area of cross section $A$ is attached to a rigid support. Another metal wire of length $L_2$ and of the same cross sectional area is attached to the free end of the first wire. A body of mass $M$ is then suspended from the free end of the second wire. If $Y_1$ and $Y_2$ are the Youngs moduli of the wires respectively, the effective force constant of the system of two wires is :
$\frac{{\left[ {\left( {{Y_1}{Y_2}} \right)A} \right]}}{{\left[ {2\left( {{Y_1}{L_2} + {Y_2}{L_1}} \right)} \right]}}$
$\frac{{\left[ {\left( {{Y_1}{Y_2}} \right)A} \right]}}{{{{\left( {{L_1} + {L_2}} \right)}^{\frac{1}{2}}}}}$
$\frac{{\left[ {\left( {{Y_1}{Y_2}} \right)A} \right]}}{{\left[ {\left( {{Y_1}{L_2} + {Y_2}{L_1}} \right)} \right]}}$
$\frac{{\left[ {{{\left( {{Y_1}{Y_2}} \right)}^{1/2}}A} \right]}}{{{{\left( {{L_1} + {L_2}} \right)}^{1/2}}}}$
A rod is fixed between two points at $20°C$. The coefficient of linear expansion of material of rod is $1.1 \times {10^{ - 5}}/^\circ C$ and Young's modulus is $1.2 \times {10^{11}}\,N/m$. Find the stress developed in the rod if temperature of rod becomes $10°C$
Figure shows graph between stress and strain for a uniform wire at two different femperatures. Then
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 ratios of their diameters if each is to have the same tension.
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area $A$ and the second wire has cross-sectional area $3A$. If the length of the first wire is increased by $\Delta l$ on applying a force $F$, how much force is needed to stretch the second wire by the same amount?
A wire of length $2\, m$ is made from $10\;c{m^3}$ of copper. A force $F$ is applied so that its length increases by $2\, mm.$ Another wire of length 8 m is made from the same volume of copper. If the force $F$ is applied to it, its length will increase by......... $cm$