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Solved: BIO Power of the Human Heart. The human heart is a
Chapter 6, Problem 95P(choose chapter or problem)
Problem 95P
BIO Power of the Human Heart. The human heart is a powerful and extremely reliable pump. Each day it takes in and discharges about 7500 L of blood. Assume that the work done by the heart is equal to the work required to lift this amount of blood a height equal to that of the average American woman (1.63 m). The density (mass per unit volume) of blood is 1.05 X 103 kg/m3. (a) How much work does the heart do in a day? (b) What is the heart’s power output in watts?
Questions & Answers
QUESTION:
Problem 95P
BIO Power of the Human Heart. The human heart is a powerful and extremely reliable pump. Each day it takes in and discharges about 7500 L of blood. Assume that the work done by the heart is equal to the work required to lift this amount of blood a height equal to that of the average American woman (1.63 m). The density (mass per unit volume) of blood is 1.05 X 103 kg/m3. (a) How much work does the heart do in a day? (b) What is the heart’s power output in watts?
ANSWER:
Solution 95P
Step 1:
Amount of blood pumped by the heart in a day, V = 7500 L
We know that, 1 m3 = 1000 L
Therefore, 1 L = 1/1000 m3
Therefore, V = 7500 × 1/1000 m3 = 7.5 m3
Density of the human blood, d = 1.05 × 103 kg/m3
Equation for calculating the density, d = ,m/V
Where, m - mass of blood
V - volume of blood’
Therefore, m = Vd
m = 7.5 m3 × 1.05 × 103 kg/m3 = 7.875 × 103 kg
The amount of blood passing through the heart in a day, m = 7.875 × 103 kg