d
\(\begin{array}{l}
\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Velocity\,of\,water\,is\,v,\,mass\\
flowing\,per\,unit\,lenght\,is\,m.\\
\therefore \,\,\,\,\,\,Mass\,flowing\,per\,{\rm{second}}\, = mv\\
\therefore \,\,\,\,\,\,\,Rate\,of\,kinetic\,energy\,or\,K.E\\
per\,{\rm{second}}\\
\,\,\,\,\,\,\,\,\,\, = \frac{1}{2}\left( {mv} \right){v^2} = \frac{1}{2}m{v^3}.
\end{array}\)