The correct match of head loss and cases are:
- (i) Sudden enlargement → \( \frac{V_1^2}{2g} \)
- (ii) Entrance of the pipe → \( \frac{V_2^2}{2g} \)
- (iii) Exit of the pipe → \( 0.5 \frac{V_2^2}{2g} \)
- (iv) Pipe fittings → \( k \frac{V_2^2}{2g} \)
A closed-loop system has the characteristic equation given by: $ s^3 + k s^2 + (k+2) s + 3 = 0 $.
For the system to be stable, the value of $ k $ is: