Absolute pressure at the bottom of a container

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SUMMARY

The absolute pressure at the bottom of a container filled with water and oil can be calculated using the formula P = ρgh + P(atmospheric). In this case, a 20.0 cm depth of water is topped with a 29.0 cm layer of oil with a specific gravity of 0.800. The correct calculation requires converting all measurements to meters and summing the contributions of both fluids without subtracting their depths. The final absolute pressure should be recalculated to ensure accuracy, as initial attempts yielded a discrepancy greater than 10%.

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kimlu
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Homework Statement



A container is filled to a depth of 20.0 cm with water. On top of the water floats a 29.0-cm-thick layer of oil with specific gravity 0.800. What is the absolute pressure at the bottom of the container?
(Answer in Pa)

Homework Equations



P= ρgh+ P(atmospheric)

The Attempt at a Solution



(800)(9.81)(29-20)+101.3x10^3= 171932

Webassign says "Your response differs from the correct answer by more than 10%. Double check your calculations."

Did I substitute something wrong?
 
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Hi kimlu...

You have to calculate pressure at the bottom of the container ,not between the interface of water and oil .

You also seem to have forgotton to convert 'cm' to 'm' .
 
Last edited:
kimlu said:

Homework Statement



A container is filled to a depth of 20.0 cm with water. On top of the water floats a 29.0-cm-thick layer of oil with specific gravity 0.800. What is the absolute pressure at the bottom of the container?
(Answer in Pa)

Homework Equations



P= ρgh+ P(atmospheric)

The Attempt at a Solution



(800)(9.81)(29-20)+101.3x10^3= 171932

Webassign says "Your response differs from the correct answer by more than 10%. Double check your calculations."

Did I substitute something wrong?

Yes.

Why did you subtract the thickness of water from the thickness of oil?

ehild
 

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