A leaf is caught in a whirlpool at a given instant, the leaf is at a distance of 120 m from the centre of the whirlpool the whirlpool can be described by the following velocity distribution;
$V_{r}=-\left ( \frac{60\times 10^{3}}{2\pi r} \right )m/s$
$V_{0}=\left ( \frac{300\times 10^{3}}{2\pi r} \right )m/s$
Where r (in meters) is the distance from the centre of the whirlpool. What will be the distance of the leaf from the centre when it has moved through half a revolution?
(a) 48m (b) 64m
(c) 120m (d) 142m