Final answer:
A. Birth (12 hours, < 1000g) To convert normal blood pressure from mm Hg to N/m², we use the relationship for fluid pressure. A typical young adult's blood pressure of 120 over 80 mm Hg converts to 1.60 × 10⁴ N/m² and 1.07 × 10⁴ N/m², respectively. Infant blood pressure is lower because of the smaller height to which their heart must pump blood.
Step-by-step explanation:
Conversion of Blood Pressure Readings To convert normal blood pressure readings from mm Hg to Newtons per meter squared (N/m²), we use the relationship for pressure due to the weight of a fluid (P = hpg), where 'h' is the height of the fluid column, 'p' is the density of the fluid, and 'g' is the acceleration due to gravity. Given that 1.0 mm Hg equals 133 Pascal (Pa) and knowing that 1 Pascal is 1 N/m², we can convert the typical systolic pressure of 120 mm Hg and diastolic pressure of 80 mm Hg into N/m². Therefore, the pressure conversions are P120 = 1.60 × 10⁴ N/m² and P80 = 1.07 × 10⁴ N/m².
Infant Blood PressureWhen considering why blood pressures for an infant could be smaller than those for an adult, it is essential to take into account the smaller height to which blood must be pumped. Due to an infant's height of approximately 20 inches compared to an adult's height of around 70 inches, it follows that the required blood pressure would be lower because the heart does not need to work as hard to pump blood over a smaller vertical distance.