MCAT Physics Question – Atmospheric Pressure

  • Reviewed By: Liz Flagge
  • The death zone on Mount Everest refers to altitudes above 8,000 meters, where oxygen levels are not sufficient to sustain human life for extended periods, causing rapid physical deterioration. Climbers in this zone face extreme risks of hypoxia, cerebral/pulmonary edema, and fatal cognitive impairment. Supplemental oxygen is required for prolonged survival. What is the atmospheric pressure at the top of Mount Everest, which stands approximately 9000 meters above sea level? (Assume an average air density = 0.8 kg/m3 and g = 10 m/s2)

    1. 7200 Pa
    2. 29000 Pa
    3. 72,000 Pa
    4. 101,000 Pa
    Click for Explanation

    This question asks the examinee to determine the pressure due to the atmosphere at the top of Mount Everest. To answer this question, you must determine the difference in air pressure between sea level (101,000 Pa) and the top of Everest. The best method to calculate the pressure differential is to apply the gauge pressure formula, Pgauge = ρgh, where Pgauge is the pressure due to the atmospheric column of height h, ρ is the density of the fluid, and g is the gravitational acceleration constant. The difference between the atmospheric pressure at sea level and the gauge pressure applying the equation above yields the atmospheric pressure at the top of Mt. Everest, as follows:

    PEverest = PSea Level – Pgauge

    PEverest = 101,000 Pa– ρgh

    PEverest = 101,000 Pa– (0.8 kg/m3)(10 m/s2)(9000 m)

    PEverest =29,000 Pa

    Thus, the correct answer is 29,000 Pa, which is answer choice B.

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