Which best describes hydrostatic pressure variation with depth?

• A. Pressure due to moving water around an object.
• B. The pressure exerted by fluid at rest due to gravity, increasing with depth.
• C. Pressure dependent only on water temperature.
• D. Pressure that only occurs at the surface.

Answer: (B)

Hydrostatic pressure is the pressure exerted by a fluid at rest due to the weight of the fluid above a point. As you go deeper, there is more water above pushing down, so the pressure increases with depth. In a simple case with constant density, this relationship is described by p = p_atm + ρ g h, meaning pressure rises linearly as depth h increases.

This matches the idea that pressure in a still liquid comes from gravity and gets stronger the deeper you go, unlike pressure from moving water (dynamic pressure) or pressures that depend on temperature or only at the surface.