Calculate work should be done (in J) in order to squeeze all water from a horizontally located cylinder as shown in figure during the time t = 10 s by means of a constant force acting on the piston? The volume of water in the cylinder is equal to V = 1 lit, the cross-sectional area of the orifice is a = 0.5 cm2, with a being considerably less than the piston area. The friction and viscosity are negligibly small.

Work done to squeeze water=F⋅LIf v be the velocity at point B, then applying Bernoull theorem at points ‘1’ and ‘2’, we have      P1+12ρv12=P2+12ρv22Here P1=P0+FA and P2=P0also v1 is very much smaller than v2, can be neglected here we haveP0+FA=P0+12ρv2         …(i)Force on piston F=P⋅A=12ρv2A         …(ii)Volume of liquid coming through orifice per unit time = a vVolume of liquid coming through during time 't' V = a v tVelocity of liquid through orifice v=VatFrom Eqs. (i) and (ii) F=12ρVat2AThus work done is W=FL=12ρVatAL=12ρVat2Vhence W=12ρV3a2t2=1210001000×10−630.5×10−42102=2.0J