Question

Each day, the human heart pumps about 7500 liters of blood. As a simple approximation, assume that the work done by the heart is equal to the work required to lift this amount of blood from a person's feet to their head. Estimate the amount of work a person's heart does in a day if that person is 1.5 m tall. (Note that the density of blood is 1050 kg/m3  and 1 liter = 0.001 m3.) Given this approximation, what is the power output of this person's heart?

Answer 1

Answer with Step-by-step explanation:

We are given

Volume of blood=V=7500 L=$7500\times 0.001=7.5 m^3$

1 liter=$0.001 m^3$

Height of person=h=1.5 m

Density of blood,$\rho=1050 kg/m^3$

We have to find the work done and power of person's heart.

We know that

Work done,$W=mgh=\rho Vgh$

Where $g=9.8 m/s^2$

Using the formula

$W=1050\times 7.5\times 9.8\times 1.5=1.16\times 10^5 J$

Time,t=1 day=$24\times 60\times 60=86400 s$

Power, P=$\frac{W}{t}$

Using the formula

$P=\frac{1.16\times 10^5}{86400}=1.34 Watt$