If block just starts moving
$\mathrm{F} \cos 60^{\circ}=\mu \mathrm{N}$
$\Rightarrow \frac{\mathrm{F}}{2}=0.5\left(\mathrm{mg}-\frac{\sqrt{3}}{2} \mathrm{F}\right)$
$\Rightarrow \mathrm{F}+\frac{\sqrt{3} \mathrm{F}}{2}=10$ or $F=\frac{20}{2+\sqrt{3}}$


$STATEMENT-2$ The magnitude of frictional force depends on the nature of the two surfaces in contact.
