Question

A patient’s heart pumps 5.00 L of blood per minute into the aorta, which has a diameter of 1.80 cm. The average force exerted by the heart on the blood is 16.5 N. What is the average mechanical power output of the heart?

Answer 1

Pressure (P) = F/A

diameter = d = 1.80 cm = 0.018 m

F = force = 16.5 N

Volume pump = 5 L = 5000 cm^3 = 0.005 m^3

Area = pi* r^2 = pi* (0.018/2)^2 = 2.54 x10^-4 m^2

P = 16.5 / 2.54 x10^-4 = 64,840.9 N/m^2

Power = w *d / time = 64,840.9 N/m^2 * 0.005 m^3 / 60 s = 5.4 Watt