Final answer:
The absolute pressure when the gauge pressure is 25 PSI at sea level on a standard day is the sum of the gauge pressure and atmospheric pressure, which equals 39.7 PSI.
Step-by-step explanation:
When discussing the pressure in fluids, it's important to understand the difference between gauge pressure and absolute pressure. Gauge pressure is the pressure measured relative to the local atmospheric pressure. Absolute pressure is the total pressure experienced by an object, which includes both the gauge pressure and the atmospheric pressure. Atmospheric pressure at sea level on a standard day is approximately 14.7 PSI (pounds per square inch).
To calculate the absolute pressure if the gauge pressure is 25 PSI, we add the atmospheric pressure:
25 PSI (gauge pressure) + 14.7 PSI (atmospheric pressure) = 39.7 PSI (absolute pressure).
Therefore, the correct answer is A. 39.7 PSI, which represents the absolute pressure when the gauge pressure is 25 PSI at sea level on a standard day.