A balloon has `8g` of air `A` small hole is pierced into it The air escapes at a unifrom rate of `7m//s` If the ballon shrinks in `5.6 s` then the average force acting on the ballon is.

Options

A. `10^(-4)N` .
B. `10^(-2) "dyne"`
C. `56 "dyne"` .
D. `10^(-6)N` .

Answer

a

Explanation

Here, `m = 8 g = (8)/(100) kg`
`upsilon = 7 cm//s = (7)/(100)m//s`
`t = 5.6 sec, F = ` ?
According to Newton s `2nd` Law :
`F = (dp)/(dt) = (d)/(dt) (mu upsilon) = (upsilon dm)/(dt)` [ `:. upsilon` is constant]
`F = (7)/(100) xx(8)/(1000 xx 5.6) = 10^(-4) N` .