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Mariana Trench Depth from Pressure
The submarine moved from the surface of the water to the bottom of the Mariana Trench. The change in pressure was 110 000 kPa. mean density of sea water = 1026 kg/m³. gravitational field strength = 9.8 N/kg. Use the Physics Equations Sheet.
Calculate the depth of the Mariana Trench.
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Marking points
- 1 Converts the pressure change from kPa to Pa.
- 2 Substitutes pressure, density and gravitational field strength into p = hρg.
- 3 Rearranges correctly for depth.
- 4 Gives 10 940 m, or 11 000 m with correct working, preserving official consequential marking.
Full-mark answer
110 000 kPa = 110 000 000 Pa. Using p = hρg, h = 110 000 000 ÷ (1026 × 9.8) = 10 940 m (about 11 000 m).
Why this answer loses marks
Uses the pressure in kilopascals directly in the depth equation.
The pressure must be converted to pascals to match the SI units used for density and gravitational field strength.