Unit-Safe Variables & Dimensional Checks

Encoding Physical Units in Variable Names

In engineering software, a number without a unit is ambiguous. Always encode SI base units directly in your variable identifiers (pressure_Pa, flow_rate_m3_s, torque_Nm).

Practical Tip SI Base Unit Convention Convert millimetres, kilonewtons, and megapascals into base SI units (m, N, Pa) immediately upon input, perform all internal math in base SI, and format back to display units only when printing.

diameter_mm = 50.0
force_kN = 18.5

# Convert to base SI units at the boundary
radius_m = (diameter_mm / 1000.0) / 2.0
force_N = force_kN * 1000.0

import math
area_m2 = math.pi * (radius_m ** 2)
stress_MPa = (force_N / area_m2) / 1e6
print(f"Cross-sectional area: {area_m2*1e4:.2f} cm^2")
print(f"Axial tensile stress: {stress_MPa:.2f} MPa")