Absolute pressure is equal to gauge pressure plus_________?

Absolute pressure is defined as the total pressure exerted on a system, taking into account both the atmospheric pressure and any additional pressure applied to it. Gauge pressure is the pressure relative to atmospheric pressure; it indicates how much pressure exists in a system compared to the surrounding atmosphere. Therefore, to convert gauge pressure to absolute pressure, you need to add the atmospheric pressure to it.

For example, if a tire has a gauge pressure of 30 psi, the absolute pressure would be obtained by adding the atmospheric pressure (approximately 14.7 psi at sea level), resulting in an absolute pressure of about 44.7 psi. This relationship is critical in many areas, including refrigeration and HVAC systems, where accurate pressure readings are essential for efficient operation and safety.

The other choices do not accurately complete the relationship of absolute pressure because they either represent different types of pressure measurements or are not directly related to the conversion from gauge pressure to absolute pressure.