A holding tank at sea level (atmospheric pressure 1.01 x 105 Pa) containing water has a pressure of 2 x 105 Pa at 10 m depth. What is the pressure in an equivalent holding tank containing mercury (specific gravity = 13) at 1 m depth in Denver, CO (atmospheric pressure 8.4 x 104 Pa)?
A. 2 x 105 Pa
B. 1 x 105 Pa
C. 1.4 x 106 Pa
D. 8.4 x 104 Pa
Click for Explanation
Here, we can simply plug in the values provided:
Ptot = (8.4 x 104) + (13,000 kg/m3 x 10m/s2 x 1m) = 2.14 x 105 Pa
A. 2 x 105 Pa correct, matches our calculation
B. 1 x 105 Pa, incorrect, this is the same pressure at sea level for 10m of water, ignores fluid change and atmospheric pressure change
C. 1.4 x 106 Pa, incorrect, this answer fails to change the fluid depth to 1m for the mercury rather than the 10m depth used for water
D. 8.4 x 104 Pa, incorrect, this answer ignores the fluid contribution to pressure and only uses the atmospheric contribution
Want more MCAT practice?
We’ve got options for every schedule and learning style!
Whether you need the flexibility of a Self-Paced Course, the instruction of a live 515+ Course, or the 1:1 attention of a private MCAT tutor, Blueprint MCAT has the MCAT prep option that works for your learning style!
Get started with a free MCAT diagnostic, one free practice exam, and tons more MCAT prep resources.
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.
