Question 169 of 210

An insect is at the bottom of a hemispherical ditch of radius $1m$. It crawls up the ditch but starts slipping after it is at height h from the bottom. If the coefficient of friction between the ground and the insect is $0.75,$ then $h$is $:\left(g=10m{s}^{-2}\right)$

A$0.20m$B$0.45m$C$0.60m$D$0.80m$

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Answer: (A) $0.20m$

$mgsin\theta =\mu mgcos\theta$
$\tan \theta =\mu =0.75$
$\Rightarrow \theta =37$
$\cos \theta =\dfrac{R-h}{R}$
$\cos 37=\dfrac{1-h}{1}\Rightarrow h=0.2$