The heart of a man pumps 5 litres of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury be 13.6 × 10 3 k g m - 3 and g = 10 m s - 2 , then the power of heart in watt is:

Question

The heart of a man pumps 5 litres of blood through the arteries per minute at a pressure of 150 mm of mercury. If the density of mercury be 13.6 × 10 3 k g m - 3 and g = 10 m s - 2 , then the power of heart in watt is:, 2.35, 3.0, 1.50, 1.70

MARKS App · Accepted Answer

$\begin{aligned} & \text { Pressure }=\mathrm{P}=150 \mathrm{~mm} \mathrm{Hg} \ & \text { Pumping rate }=\frac{\mathrm{dV}}{\mathrm{dt}}=\frac{5 \times 10^{-3}}{60} \mathrm{~m}^3 / \mathrm{s} \ & \text { Power of heart }=\text { P. } \frac{\mathrm{dV}}{\mathrm{dt}}=\rho \mathrm{gh} \times \frac{\mathrm{dV}}{\mathrm{dt}} \ & =\left(13.6 \times 10^3\right)(10) \times(0.15) \times \frac{5 \times 10^{-3}}{60} \ & =\frac{13.6 \times 5 \times 0.15}{6}=1.70 \mathrm{watt}\end{aligned}$

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