Rain is falling vertically downwards with the velocity of 30m/s, a wind blows from north to south direction with 10m/s then at what angle should the umbrella of the person be held and in which direction.
Difficulty: Easy
A:
$\tan^{-1}\left(\frac{1}{3} \right)$ vertical towards north
B:
$\tan^{-1}\left(\frac{1}{3} \right)$ vertical towards south
C:
$\cos^{-1}\left(\frac{1}{3} \right)$ vertical towards north
D:
$\cos^{-1}\left(\frac{1}{3} \right)$ vertical towards south
