\( 4.5 \times 10^4-2.0 \times 10^4=\frac{1}{2} \times 10^3 \times \mathrm{v}^2 \)
\( 2.5 \times 10^4=\frac{1}{2} \times 10^3 \times \mathrm{v}^2 \)
\( \mathrm{v}^2=50 \)
\( \mathrm{v}=\sqrt{50} \)
\( \text { Velocity of water }=\sqrt{\mathrm{V}}=\sqrt{50} \)
\( =\mathrm{V}=50\)