Question

Raindrops are falling vertically at a speed of 120 km/h through air that is moving horizontally at a speed of 40 km/h(i.e. the wind is 40 km/h). At what angle do the drops strike the ground?

Answer 1

`18^@` from vertical or `72^@` from horizontally.

Explanation:

Air is moving horizontally with 40 km/h speed
Horizontal velocity vector of Air is shown in figure.

Velocity Vector of Raindrops is vertically downward .
Let resulting Velocity of Raindrops makes angle `theta` from the
vertical.
Then angle
`tantheta=v_"Horizontal"/v_"vericle"=40/120=1/3`

`theta=tan^-1(1/3)approx18^@`

Hence Raindrops makes angle `18^@` from the vertical or make angle `72^@` from Horizontal.