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The human heart pumps the average adult’s 6.0 L (6000 cm3)
Chapter 11, Problem 63P(choose chapter or problem)
Problem 63P
The human heart pumps the average adult’s 6.0 L (6000 cm3) of blood through the body every minute. The heart must do work to overcome frictional forces that resist blood flow. The average adult blood pressure is 1.3 × 104 N/m2.
a. How much work does the heart do to move the 6.0 L of blood completely through the body?
b. What power output must the heart have to do this task once a minute?
Hint: When the heart contracts, it applies force to the blood. Pressure is force/area. Model the circulatory system as a single closed tube, with cross-section area A and volume V =6.0 L, filled with blood to which the heart applies a force.
Questions & Answers
QUESTION:
Problem 63P
The human heart pumps the average adult’s 6.0 L (6000 cm3) of blood through the body every minute. The heart must do work to overcome frictional forces that resist blood flow. The average adult blood pressure is 1.3 × 104 N/m2.
a. How much work does the heart do to move the 6.0 L of blood completely through the body?
b. What power output must the heart have to do this task once a minute?
Hint: When the heart contracts, it applies force to the blood. Pressure is force/area. Model the circulatory system as a single closed tube, with cross-section area A and volume V =6.0 L, filled with blood to which the heart applies a force.
ANSWER:
Step 1 of 4
Part (a)
We are going to find the work done by the heart to pump the blood through the body.
The average volume of blood pumped \(\mathrm{V}=6 \mathrm{~L}=6 \times 10^{-3} \mathrm{~m}^{3}\)
The average pressure \(\mathrm{P}=1.3 \times 10^{4} \mathrm{~N} / \mathrm{m}^{2}\)