(c) For the rolling a solid cylinder acceleration $a = \frac{g}{3}\sin\theta$
[image:7_image119.emf]
$\therefore$ The condition for the cylinder to remain in equilibrium
$Ma \leq \mu\ sR$
$\Rightarrow$ $\frac{1}{2}Mg\sin{\theta \leq Mg\cos{\theta.\mu_{s}}}$
or $\mu_{s} \geq \frac{1}{3}\tan\theta$
or $\tan{\theta \leq 3\ \mu_{s}}$