Force, Impulse, and Momentum

Pressure on Area Makes Force

Radiation pressure becomes force only after multiplying by illuminated area. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Pressure over area makes force

The illuminated area is checked before the force label is accepted.

F=pAs=1⋅3=3 NF=pA_s=1\cdot 3=3\ \text{N}
Radiation forcePressure and surface area make force.pressureSource=boundilluminatedArea=3 m^2force=3 N

Pressure alone is not force

The force label is separate from the pressure label.

As=3 m2A_s=3\ \text{m}^{2}
Area-bound forceSurface area cannot be skipped.pressureSource=boundilluminatedArea=3 m^2force=3 N