A river of salty water is flowing with a velocity `2m//sec`. If the density of water is `1.2 gm//c c`, the kinetic energy of each of cubic metre of water is

Options

A. 2.4 J
B. 24 J
C. 2.4 kJ
D. 4.8 kJ

Answer

C

Explanation

Given, velocity of river, `v=2" ms"^(-1)`
Density of water, `p=1.2" gcc"^(-1)`
Mass of each cubic metre,
`m=(1.2xx10^(-3))/((10^(-2))^(3))=1.2xx10^(3)"kg"`
`:.` Kinetic energy `=(1)/(2)" mv"^(2)`
`=(1)/(2)xx1.2xx10^(3)xx(2)^(2)`
`=2.4xx10^(3)"J"=2.4" kJ"`