Question

Find out the load to be suspended at the end of a brass wire of length 8 m to stretch it through 1 cm. The diameter of the wire = 0.4 mm. Young's Modulus = 90 GPa.

Answer 1

Answer:

$\circ\circ\circ\fbox{\fbox{\fbox{\underline{\underline{\Huge{\texttt{1.442 kg}}}}}}}\circ\circ\circ$

Explanation:

$Y=90\text{ GPa}=90\times 10^{9}\text{ Pa};\:\:\:\:\:L=8\text{ m};\:\:\:\:\:l=1\text{ cm}=1\times10^{-2}\text{ m}$

$r=0.2\text{ mm}=2\times10^{-4}\text{ m};\:\:\:\:g=9.8\text{ ms}^{-2};\:M=?;\:Y=\dfrac{MgL}{\pi r^2l}$

$M=\dfrac{Y\pi r^2l}{gL}=\dfrac{90\times10^9\times3.14\times(2\times10^{-4})^2\times1\times10^{-2}}{9.8\times8}=\bold{1.442}\bold{\:kg}$