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 × 10³ kg/m³ and g = 10 m/s², then the power of the heart in watt is:

1.7

2.35

1.5

Power: P = →F ⋅ →v = PAv = ρgh × (volume/sec) = (13.6 × 10³) × 10 × (150 × 10⁻³) × (5 × 10⁻³ / 60) = 1.7 Watt