Question

One end of a steel wire is fixed to the ceiling of an elevator moving up with an acceleration \( 2 \, \text{m/s}^2 \) and a load of 10 kg hangs from the other end. If the cross-section of the wire is \( 2 \, \text{cm}^2 \), then the longitudinal strain in the wire will be (Take \( g = 10 \, \text{m/s}^2 \) and \( Y = 2.0 \times 10^{11} \, \text{N/m}^2 \)).

• A. \( 4 \times 10^{-11} \)
• B. \( 6 \times 10^{-11} \)
• C. \( 8 \times 10^{-6} \)
• D. \( 2 \times 10^{-6} \)

Hint:

When calculating strain, the force is related to both the gravitational force and any additional forces due to acceleration. The strain is the ratio of stress to Young's modulus.