Question

A string tied on a roof can bear a maximum tension of $50kgwt$. The minimum acceleration that can be acquired by a man of $98kg$ to descend will be (Take $g=9.8m/s^2$)

• A. $9.8m/s^2$
• B. $4.9m/s^2$
• C. $4.8m/s^2$
• D. $5m/s^2$

Answer 1

Answer: (C)

$4.8m/s^2$

$T_{max}=50kgwt$

$w=98kgwt$

But $a=\frac{w-T}{m}$

${}^{\prime }{a}^{\prime }$ is maximum when $T$ is maximum.

$a_{min}=\frac{Ww-T_{max}}{m}=\frac{98-50}{98}=\frac{48}{98}$

$\frac{48\times 9.8}{98}=4.8m/s^2$