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AP® Physics 1 & 2

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Speed of Particles in Atmosphere of Mars

APPH12-KYIKES

The atmosphere of Mars consists primarily of carbon dioxide ($\mathrm{C{ O }_{ 2 }}$), but contains trace amounts of nitrogen ($\mathrm{{N}_{2}}$), oxygen ($\mathrm{{ O }_{ 2 }}$), and argon ($\mathrm{Ar}$).

Assume temperature is constant. A list of approximate atomic masses are given below.

$\mathrm{C}: 12\ \mathrm{ amu}$
$\mathrm{O}: 16\ \mathrm{amu}$
$\mathrm{N}: 14\ \mathrm{amu}$
$\mathrm{Ar}: 40\ \mathrm{amu}$

Which of the four given gases in the atmosphere of Mars is moving with the lowest average speed?

A

$\mathrm{Ar}$

B

$\mathrm{{N}_{2}}$

C

$\mathrm{{ O }_{ 2 }}$

D

$\mathrm{C{ O }_{ 2 }}$