A hose pipe has a diameter of `2.5 cm` and is required to direct a jet of water to a height of atleast `40 cm`. Find the minimum power of the pump needed for this hose.

Explanation

Volume of water ejected per sec
`Av = pi((d)/(2))^(2) xx sqrt(2gh) m^(2) //s, :. v = sqrt(2gh)`.
Mass ejected per sec is `M = (1)/(4) pi d^(2) xx sqrt (2gh) rho Kg//s`
Kinetic energy of water leaving hose/sec
`K.E = (1)/(2)mv^(2) = (1)/(8) pi d^(2) xx(2gh)^((3)/(2)) xx rho`
=`(1)/(8) xx 3.14 xx(2.5 xx 10^(-2)) xx (2 xx 9.8 xx 40)^((3)/(2)) xx 1000 = 21.5 KJ`.