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?