Pressure Flashcards – Cambridge IGCSE (9–1) Physics 0972 (Extended) (2026–2028)

What is pressure?

The force acting perpendicular to a surface per unit area.

What equation gives pressure for a force distributed uniformly over an area? Define the symbols.

$p = \frac{F}{A}$ where $p$ is pressure, $F$ is force and $A$ is the area over which it acts.

What is the SI unit of pressure, expressed in newtons per square metre?

The pascal: $1\,\mathrm{Pa} = 1\,\mathrm{N/m^2}$.

How does increasing force affect pressure when the area is fixed?

It increases the pressure.

How does contact area affect pressure when the force is fixed?

A smaller area gives greater pressure; a larger area gives lower pressure.

How and why does pressure beneath a liquid surface change with depth?

Pressure increases with depth because there is more liquid above, whose weight produces greater pressure.

How and why does liquid density affect pressure at the same depth?

A denser liquid produces greater pressure because the same volume of liquid above has greater weight.