The source uses a fixed air density of one point two two five kilograms per cubic meter and dynamic pressure one half density times wind speed squared. At thirty meters per second this is five hundred fifty one point two five pascals. At fifteen meters per second it is one hundred thirty seven point eight one two five, a quarter. Bars share seven tenths of a pixel per pascal. This simplified demonstration is not a code-compliant design load, measured weather, structural certification or a safety approval. The default ten by five meter face at thirty meters per second gives twenty seven point five six two five kilonewtons at zero angle. The source multiplies pressure by cosine angle and projected area by cosine angle, so sixty degrees yields one quarter force, about six point eight nine zero six kilonewtons. Bars share fourteen pixels per kilonewton. This is the implemented cosine-squared rule, not independently validated aerodynamics, a drag model or a claim about a real billboard. The default force acts at half the five-meter height, giving sixty eight point nine zero six two five kilonewton meters overturning moment. The source assumes ten anchors, each fifty kilonewtons, with depth divided by two as lever arm, yielding seventy five kilonewton meters resistance. Bars share five pixels per kilonewton meter. Their ratio is about one point zero nine; the source labels above one safe, but this is only its authored threshold, not a real safety determination. The entered material density is read but unused by this formula; foundations, code factors, fatigue and actual anchor behavior are absent.