The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship is given by
A
$$\frac{{2\left( {{{\text{V}}_{\text{r}}} - {\text{v}}} \right){\text{v}}}}{{{\text{V}}_{\text{r}}^2}}$$
B
$$\frac{{2\left( {{{\text{V}}_{\text{r}}} + {\text{v}}} \right){\text{v}}}}{{{\text{V}}_{\text{r}}^2}}$$
C
$$\frac{{\left( {{{\text{V}}_{\text{r}}} - {\text{v}}} \right){\text{v}}}}{{{{\text{V}}_{\text{r}}}}}$$
D
$$\frac{{\left( {{{\text{V}}_{\text{r}}} + {\text{v}}} \right){\text{v}}}}{{{{\text{V}}_{\text{r}}}}}$$
Correct Answer: $$\frac{{2\left( {{{\text{V}}_{\text{r}}} - {\text{v}}} \right){\text{v}}}}{{{\text{V}}_{\text{r}}^2}}$$
