At zero wind speed rain water falls vertically with velocity V`cm *s^(-1)` and is collected in a pot at a fixed rate. How will the rate of collection of rain water change when wind is blowing with a velocity of W`cm*s^(-1)` perpendicular to V ?

Explanation

There will be no change in the rate of collection of rain water due to wind velocity.
Rain water falls vertically in the pot, when there is no wind [Fig.2.72(a)]. If A `cm^2` is the area of cross section of the pot, rate of collection of rain water is, `x=AV cm^3*s^(-1)` .........(1)
Because of the wind , water will be filled in the pot obliquely [Fig.2.72(b)]. The component of the cross -sectional area of the pot perpendicular to the velocity of rain , is `A_1 =A cos theta`.

Here, the effective velocity of rain is `V_1=V/(cos theta)` [Fig.2.72(c)]
Hence, rate of collection of water,
`x_1 =A_1*V_1`
`=A cos theta*V/(cos theta)=AV cm^3 *s^(-1)` .......(2)
Thus, from (1) and (2) , it is inferred that the rate of collection of rain water remains the same.