Final answer:
The blood pressure at the top of the head would be lower than the pressure at the heart due to the hydrostatic pressure difference caused by the 30 cm height difference between the heart and the head.
Step-by-step explanation:
The blood pressure difference between the heart and the top of the head in a human body can be calculated by using the principle of hydrostatic pressure. Given that the heart is approximately 30 cm above the heart, and using the density (ρ) of mercury (13.6 g/cm³) and the acceleration due to gravity (g = 9.81 m/s²), we can find the blood pressure difference.
Blood pressure changes due to the height difference in the columns of blood because of the equation P = hρg, where P is the pressure, h is the height difference, ρ is the density of the fluid, and g is the acceleration due to gravity. Since 1.0 mm Hg is equivalent to 133 Pa, an increase in height will result in an increased measurement in mm Hg when measuring blood pressure below the heart. Therefore, at the top of the head (0.30 m above the heart), the pressure measured would be less than the pressure at the level of the heart due to the change in hydrostatic pressure.