When a horizontal laminar flow occurs between two parallel plates of infinite extent \(0.3 \mathrm{~m}\) apart, the velocity at the midpoint between the plates is \(2.7 \mathrm{~m} / \mathrm{s}\). Calculate

(a) the flow rate through a cross section \(0.9 \mathrm{~m}\) wide,

(b) the velocity gradient at the surface of the plate,

(c) the wall shearing stress if the fluid has viscosity \(1.44 \mathrm{P} \cdot \mathrm{s}\), and

(d) the pressure drop in each \(30 \mathrm{~m}\) along the flow.