The power of a heart which pumps $5 \times {10}^3 \mathrm{cc} \mathrm{of} \mathrm{blood} \mathrm{per} \mathrm{minute} \mathrm{at} \mathrm{a} \mathrm{pressure} \mathrm{of} 120 \mathrm{mm} \mathrm{of} \mathrm{mercury} (\mathrm{g} = 10 {\mathrm{ms}}^{-2})$and density of Hg = $13.6\times {10}^3 \mathrm{kg}/{\mathrm{m}}^3) \mathrm{is}$