A human heart pumps 60 cc of blood through the arteries at each beat against an average pressure 10 cm of mercury.   If the pulse beats 72 times in a minute, the pumping power of heart will be nearly(Density of mercury  =   13.6 gm/cc,     g   =   10cm/s2)

Power    =    Worktime   =    Pressure⋅Volumet   =    hdg⋅Vt given height h=10cm=0.1m; density of mercury d=13.6x103kg/m3;acceleration due to gravity g=10m/s2;volume v=60x10-6m3 time for 1 heart beat=6072 Power=0.1×13.6×103×10×60×10−66072 Power=0.9792  ≃  1 Watt