Solving Pressure & Force Homework Problem

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SUMMARY

The problem involves calculating the force required to lift a lid from a box with specific dimensions and an internal pressure of 7.2e4 Pa. The correct formula used is P=F/A, where F is the force, P is the pressure difference, and A is the area of the lid. The area is calculated using the box dimensions (0.10 m x 0.16 m), resulting in a force of 448 N. The initial error was due to using an inaccurate atmospheric pressure value; the correct atmospheric pressure should be 101325 Pa, leading to a revised calculation of force.

PREREQUISITES
  • Understanding of pressure calculations in physics
  • Familiarity with the formula P=F/A
  • Ability to convert units from centimeters to meters
  • Knowledge of atmospheric pressure values at sea level
NEXT STEPS
  • Review the concept of pressure and force in fluid mechanics
  • Learn about unit conversions, specifically between metric units
  • Study the effects of atmospheric pressure on various physical systems
  • Explore practical applications of pressure calculations in engineering
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Students in physics or engineering courses, educators teaching pressure concepts, and anyone needing to solve real-world problems involving force and pressure calculations.

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Homework Statement



"A lid is put on a box that is 10 cm long, 16 cm wide, and 8.0 cm tall and the box is then evacuated until its inner pressure is 7.2e4 Pa."

How much force is required to lift the lid at sea level?

Homework Equations



I know that I have to use P=F/A
I changed my centimeters to meters also, although I'm not sure you have to.

The Attempt at a Solution



I used F = PA
F= (Atmospheric pressure - inner pressure)(lxw)
F=(100000 - 72000)(.10x.16)
F=(28000)(.016)
F=448 N

I tried this answer but got it wrong. Can someone please point me in the right direction? Thanks!
 
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I figured it out! I just used a more accurate number for my atmospheric pressure instead of simply 10000.
 

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