Question

A metal block of mass m is suspended from a rigid support through a metal wire of diameter 14 mm. The tensile stress developed in the wire under equilibrium state is 7× 10⁵ Nm^-2 . The value of mass m is ___ kg. (Take, g = 9.8 ms-2 and π =\(\frac{ 22}{7}\))

Answer 1

Correct Answer: 11

Using stress = \(\frac{\text{force}}{\text{area}} = \frac{mg}{A}\)
\[ \Rightarrow m = \frac{S \times A}{g} \] \[ m = \frac{7 \times 10^5 \times \pi \times (7 \times 10^{-3})^2}{9.8} \] \[ m = \frac{7 \times 10^5 \times \frac{22}{7} \times (7 \times 10^{-3})^2}{9.8} \] \[ m = 11 \, \text{kg} \] (Note: \(14 \, \text{mm}\) is diameter)