A non-viscous liquid of constant density 103 kg/m3 flows in streamline motion along a vertical tube PQ of variable cross-section. Height of P and Q are 2m and 2.5mrespectively. Area of tube at Q = 3 time area of tube at P. Find the work done per unit volume (in J/m3) by pressure as liquid flows from P to Q. Speed of liquid at P is 3 m/s(g = 10 m/s2).