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Jamesey162
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Homework Statement
A tyre contains gas at a pressure of 150 kPa. If the gas has a density of 2.0 kg m-3, find the root mean square speed of the molecules.
Homework Equations
These are the equations I believe to be relevant:
[tex]c_{rms} = \frac{\sqrt{<c^2>}}{N}[/tex]
[tex]pV = \frac{1}{3}Nm<c^2>[/tex]
[tex]p = \frac{1}{3}ρ<c^2>[/tex]
The Attempt at a Solution
[tex]\frac{3p}{ρ} = <c^2>[/tex]
[tex]\frac{3 * 150000}{2} = <c^2> = 225000ms^{-1}[/tex]
But I'm not sure how to work out N as I don't any volume or temperature. I'm not quite sure how they get their answer in the back of the book which is 474 ms-1 (which is the square root of 225000) meaning that N = 1? How can that be?
Thank you for reading!
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