Question

A lift of mass $m$ is connected to a rope which is moving upward with maximum acceleration $a$. For maximum safe stress, the elastic limit of the rope, is $T$. The minimum diameter of the rope is (g = gravitational acceleration)

• A. $\left[ \frac{2m (g + a)}{\pi T } \right]^{\frac{1}{2}}$
• B. $\left[ \frac{4m (g + a)}{\pi T } \right]^{\frac{1}{2}}$
• C. $\left[ \frac{m (g + a)}{\pi T } \right]^{\frac{1}{2}}$
• D. $\left[ \frac{2m (g + a)}{2 \pi T } \right]^{\frac{1}{2}}$

Answer 1

Answer: (B)

$\left[ \frac{4m (g + a)}{\pi T } \right]^{\frac{1}{2}}$

Answer 2

Answer (b) $\left[ \frac{4m (g + a)}{\pi T } \right]^{\frac{1}{2}}$