Question

With what minimum acceleration can a fireman slide down a rope while breaking strength of the rope is $\frac{2}{3}$ of the weight?

• A. $\frac{2}{3}g$
• B. $g$
• C. $\frac{1}{3}g$
• D. Zero

Answer 1

The correct option is C $\frac{1}{3}g$

Let the weight of the fireman be $mg$ and his downward acceleration be $a$.

Breaking strength of rope $T=\frac{2}{3}mg$ (given)

$\therefore$ $ma=mg-T$

OR $ma=mg-\frac{2}{3}mg$

OR $ma=\frac{1}{3}mg$ $⟹a=\frac{g}{3}$