Last problem and I have no idea how to do this. The human heart has to pump the

Question

Last problem and I have no idea how to do this.

The human heart has to pump the average adult's 5.9 L of blood through the body every minute. The heart must do work to overcome frictional forces that resist the blood flow. The average blood pressure is 1.3×10^4 N/m^2.

A.)Compute the work done moving the 5.9 L of blood completely through the body, assuming the blood pressure always takes its average value. Hint: When the heart contracts, it applies force to the blood. Pressure is just force/area so we can write work = (pressure)(area)(distance). But (area) (distance) is just the blood volume passing through the heart.

Answer Should be in J.

B.)What power output must the heart have to do this task once a minute?

Answer Should be in W.


Thanks in advance!

Explanation / Answer

Data: Volume, V = 5.9 L                   = 5.9 x 10^-3 m^3 Pressure, p = 1.3 x 10^4 N/m^2 Solution: (a) Work, W = Pressure * Volume                 = 1.3 x 10^4 * 5.9 x 10^-3                 = 76.7 J Ans: Work, W = 76.7 J (b) Time, t = 1 minute             = 60 s Power, P = W / t                = 76.7 / 60                = 1.28 W Ans: Power, P = 1.28 W

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