Pressure

Pressure is the normal force exerted per unit area:

$P = \frac{F}{A}$

where $F$ is force in Newtons and $A$ is area in m². The SI unit of pressure is the Pascal (Pa = N/m²).

Standard Atmosphere

Standard atmospheric pressure at sea level is defined as:

$P_{\text{atm}} = 101\,325\,\text{Pa} = 101.325\,\text{kPa} \approx 1\,\text{bar}$

Absolute vs Gauge Pressure

Most pressure gauges measure gauge pressure — pressure relative to the local atmosphere. Absolute pressure is the total pressure including the atmosphere:

$P_{\text{abs}} = P_{\text{gauge}} + P_{\text{atm}}$

$P_{\text{gauge}} = P_{\text{abs}} - P_{\text{atm}}$

A gauge reading of zero means the pressure equals atmospheric — not a vacuum.

Conversion Examples

Your Task

Implement:

• pressure(F, A) — force divided by area (Pa)
• gauge_to_absolute(P_gauge) — add atmospheric pressure
• absolute_to_gauge(P_abs) — subtract atmospheric pressure