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Q & A: MKS units for pressure

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Most recent answer: 12/14/2013
Q:
i learned from school that liquid pressure is calculated from the formula P=d*g*h where P is pressure, d is density, g is 10m/s^2 i.e. gravity, and h is height. so this formula could be used, for example, to find the atmospheric pressure measured by a mercury barometer. but for h, would i write it in cm or mm?
- Nanditha (age 15)
Zenica, Bosnia and Hercigovina
A:

Hello Nanditha,

If you want to stick with standard MKS or SI units then you should express the density, d,  in kilograms per meter cubed, the acceleration due to gravity, g, in meters per second squared, and the height, h,  in meters. The SI unit for pressure is the pascal (Pa), equal to one newton per square meter (N/m2 or kg·m−1·s−2)

 

LeeH


(published on 12/14/2013)

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