Final answer:
The observed blood pressure in a leg 0.500 m below the heart would be the same as at the heart, which is 120/80 mm Hg.
Step-by-step explanation:
Calculating Blood Pressure
To calculate the pressure observed when measuring blood pressure in a leg 0.500 m below the heart, we can use the concept of hydrostatic pressure. In this case, we can assume that the pressure at the heart is 120 mm Hg during systole and 80 mm Hg during diastole. Since there is no loss of pressure due to resistance, the pressure observed in the leg would be the same as at the heart. Therefore, the observed pressure would be 120/80 mm Hg.