Consider two non-interacting tanks-in-series as shown in figure. Water enters TANK 1 at q cm³/s and drains down to TANK 2 by gravity at a rate k√h (cm³/s). Similarly, water drains from TANK 2 by gravity at a rate of k√h₂ (cm³/s) where h₁ and h₂ represent levels of TANK 1 and TANK 2, respectively (see figure). Drain valve constant k = 4 cm^2.5/s and cross-sectional areas of the two tanks are A₁ = A₂ = 28 cm². At steady state operation, the water inlet flow rate is q_ss = 16 cm³/s. The transfer function relating the deviation variables h''₂(s) (cm) to q''(s) (cm³/s) is,