Question

A man walks at 5 km/h in the direction of a 20-km/h wind. raindrops fall vertically at 9.4 km/h in still air. determine the direction in which the drops appear to fall with respect to the man, measured clockwise from the direction of the wind.

Answer 1

Since when the person runs at 8 km/h the rain seems to be coming verticaly down thus the horizontal component of rain, Vx is 8 km/h

When he incrreases his relative speed by 4 km/h with the horizontal component of rain, it seems to fall at an angle of 30 degrees with the vertical.

It means the vertical component, Vy is: 4/Vy = tan 30

i.e.

Vy = 6.93 km/h

V = 10.58 km/h

and angle of falling is: tan-1(8/6.93)