Question

The pressure on a swimmer 20 m below the surface of water at sea level is

• A. 1.0 bar
• B. 2.0 bar
• C. 2.5 bar
• D. 3.0 bar

Answer 1

Answer: (D)

3.0 bar

Answer 2

Hydrostatic Pressure Calculation:

$P_{\text{water}} = \rho g h = (10^3 \, \text{kg/m}^3)(10 \, \text{m/s}^2)(20 \, \text{m}) = 200,000 \, \text{Pa} = 2.0 \, \text{bar}$

(Since $1 \, \text{bar} \approx 10^5 \, \text{Pa}$.)

Total Pressure:

$P_{\text{total}} = \text{Atmospheric pressure} + P_{\text{water}} = 1.0 \, \text{bar} + 2.0 \, \text{bar} = 3.0 \, \text{bar}$

Pressure = Atmospheric pressure + hydrostatic pressure = $1.0 \, \text{bar} + 2.0 \, \text{bar} = 3.0 \, \text{bar}$.