Raindrops falling with terminal velocity strikes on a surface normally. Force exerted by thedrops per unit area is F. If the number of drops striking the surface per unit time become sone fourth and size of drops become double then force on the roof per unit area will be

Options

A. F
B. 4F
C. 8F
D. 16F

Answer

C

Explanation

Force on surface will depend on product of number of drops and momentum of drops
`F = n xxm V`
`n ^(1) =n/4 m ^(1) =8m v ^(1) =4v`
`F^(1) =8F`