A glass wind screen whose inclination with the vertical can be changed is mounted on a car. The car moves horizontally with a speed of 2 m/s. At what angle α with the vertical should the screen be placed so that the rain drops falling downwards with velocity 6 m/s strike the windscreen perpendicularly?
tan−1(3)
Velocity of rain with respect to car −−→vRC=−→vR−−→vC should be perpendicular to the wind screen. i.e. net components of −→vR
tan α=VCVR=26=1/3α=tan−1(1/3)