Rank the pressures from highest to lowest:

(a) bottom of a 20-cm-tall container of salt water,
(b) bottom of a 20-cm-tall container of fresh water, and
(c) bottom of a 5-cm-tall container of mercury.

P₃ > P₁ > P₂

Explanation:

To rank pressure of the given situation

a) we know

  Pressure at height h below

      P = ρ g h

density of salt water, ρ = 1029 kg/m³

      P₁ = 1029 x 10 x 0.2

      P₁ = 2058 Pa

b) density of fresh water, ρ = 1000 kg/m³

      P₂ = 1000 x 10 x 0.2

      P₂ = 2000 Pa

c) density of mercury, ρ = 13593 kg/m³

      P₃ = 13593 x 10 x 0.05

      P₃ = 6796.5 Pa

Rank of Pressures from highest to lowest

        P₃ > P₁ > P₂