Question

The breaking stress of aluminium is $7.5\times 10^{7}N{m}^{-2}$. The greatest length of aluminium wire that can hang vertically without breaking is (Density of aluminium is $2.7\times 10^{3}kg{m}^{-3}$ )

• A. $283\times 10^{3}m$
• B. $28.3\times 10^{3}m$
• C. $2.83\times 10^{3}m$
• D. $0.283\times 10^{3}m$

Answer 1

Answer: (C)

Breaking stress $=\rho \times g\times L$
Substitute values from the question
Breaking stress $=7.5\times 10^{7}N{m}^{-2}$
$\rho =$ Density of material
$g=$ Acceleration due to gravity
$L=$ Length of wire that can hang without breaking
$\rho =2.7\times 10^{3}kg{m}^{-3}$
$g=9.8m/s$
$7.5\times 10^7=2.7\times 10^3\times 9.8\times L$
$\frac{7.5\times 10^7}{2.7\times 10^3\times 9.8}=L$
$2.83\times 10^{3}m=L$