How Do Water and Mercury Pressures Compare in Different Height Containers?

AI Thread Summary
In comparing the pressures of water and mercury in containers of different heights, the pressure from water at 10 cm is calculated as 10 g/cm², while the pressure from mercury at 5 cm is 70 g/cm². The ratio of mercury pressure to water pressure is 7:1, indicating that mercury exerts significantly more pressure due to its higher density. However, when considering total pressure at the bottom of the containers, atmospheric pressure must also be factored in, which alters the ratio slightly. The difference in pressures remains independent of atmospheric pressure, emphasizing the importance of density and height in pressure calculations. Understanding these principles is crucial for accurately comparing fluid pressures in various contexts.
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Homework Statement


If you have two containers one with water (filled to 10cm) and one with mercury (5cm), how do the pressure of water and mercury compare?

p of water = 1 gm/cm^3
p of mercury = 14 gm/cm^3

Homework Equations



P = pgh where p is density, and h is height

The Attempt at a Solution



P water = (1)(10) = 10 (I am not include gravity since its the same for both and they are only looking for a ratio)

P mercury = (14)(5) = 70

Would the correct answer be: 7*Pwater = Pmercury ?
 
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Correct, although if they were looking for the RATIO of total pressure at the bottom of the two containers then you do have to consider the air pressure.
70 / 10 is not quite the same as 70+atm / 10+atm (ps. 1 atm is roughly 1000g/cm^2)
The DIFFERENCE between the pressures doesn't depend on the atmosphere.
 
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