What is Air pressure: Definition and 209 Discussions

Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa; 1,013.25 mbar), which is equivalent to 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. Pressure measures force per unit area, with SI units of pascals (1 pascal = 1 newton per square metre, 1 N/m2). On average, a column of air with a cross-sectional area of 1 square centimetre (cm2), measured from mean (average) sea level to the top of Earth's atmosphere, has a mass of about 1.03 kilogram and exerts a force or "weight" of about 10.1 newtons, resulting in a pressure of 10.1 N/cm2 or 101 kN/m2 (101 kilopascals, kPa). A column of air with a cross-sectional area of 1 in2 would have a weight of about 14.7 lbf, resulting in a pressure of 14.7 lbf/in2.

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  1. D

    Air pressure needed for ballast

    A submarine is submerged to a depth of 3150 ft in the Atlantic Ocean. What air pressure (in kpa) is needed to blow water out of the ballast tanks? I know the answer is 9410 kpa but I have been going in circles trying to figure this out. P=hd using seawater density of 64.0 pound feet cubed...
  2. B

    Does More Air Pressure Increase or Decrease Trumpet Volume?

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  3. F

    Air pressure difference in inside and outside of house

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  4. T

    Air Pressure - Kinetic Energy

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  5. P

    Solving Air Pressure Concepts in Torricelli Experiment

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  6. T

    Equal Amplitude for Active Noise Control Headphones?

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  7. V

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  8. S

    Would you run faster in lower air pressure?

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  9. L

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  10. T

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  11. J

    Air pressure variation with height

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  12. A

    What is the Relationship Between Weight and Air Pressure?

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  13. N

    Air Pressure and Net Force on a Door in a Tornado

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  14. 8

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  15. M

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  16. R

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  17. M

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  18. A

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  19. S

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  20. V

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  21. A

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  22. J

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  23. R

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  24. F

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  25. S

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  26. M

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  27. D

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  28. S

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  29. kach22i

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  30. N

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  31. T

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  32. D

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  33. P

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  34. N

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  35. R

    How Can You Increase Air Pressure in Pipes?

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  36. C

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  37. P

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  38. P

    Find force when given air pressure and volume

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  39. J

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  40. P

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  41. K

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  42. D

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  43. S

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  44. P

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  45. A

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  46. B

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  47. M

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  48. I

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  49. D

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  50. D

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