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Translational Kinetic Energy

المؤلف:  Professor John W. Norbury

المصدر:  ELEMENTARY MECHANICS & THERMODYNAMICS

الجزء والصفحة:  p 231

1-1-2017

3062

Translational Kinetic Energy

For a single molecule its average kinetic energy is

and using  gives .

Remember that M is the molar mass, which is the mass of 1 mole of gas and m is the mass of the molecule. Thus  mole = 6.02 ×10²³ = NA, Avagadro's number. Thus or

This is a very interesting result. For a given temperature T, all gas molecules, no matter what their mass, have the same average translational kinetic energy.

Example In the center of the Sun the particles are bare hydrogen nuclei (protons). Calculate their average kinetic energy.

Solution The center of the Sun is at a temperature of about 20,000,000^oK. Thus