With what minimum acceleration can a firem

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

A

$\frac{2}{3}g$

B

$g$

C

$\frac{1}{3}g$

D

Zero

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

If man slides down with some acceleration then its apparent weight decreases. For critical condition rope can bear only $2/3$ of his weight.

If $a$ is the minimum acceleration then,

Tension in the rope $ = m(g - a)$ = Breaking strength

$⇒$ $m(g - a) = \frac{2}{3}mg$

$⇒$ $a = g - \frac{{2g}}{3} = \frac{g}{3}$