Question

e human heart has to pump the average adult's 6.2L 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 1.4×10^4 N/m^2 .Part ACompute the work done moving the 6.2 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.W= ? JPart BWhat power output must the heart have to do this task once a minute?P= ? W

Answer 1

86.8 Joules

1.4466 Watts

Step-by-step explanation:

V = Volume of blood = 6.2 L =
`6.2* 10^(-3)\ m^3`

p = Pressure =
`1.4* 10^4\ N/m^2`

t = Time taken = 1 minute = 60 seconds

Work done is given by

`W=pV\\\Rightarrow W=1.4* 10^4* 6.2* 10^(-3)\\\Rightarrow W=86.8\ J`

The work done by the heart is 86.8 Joules

Power is given by

`P=(W)/(t)\\\Rightarrow P=(86.8)/(60)\\\Rightarrow P=1.4466\ W`

The output power of the heart is 1.4466 Watts