Explain why the average velocity of the gas molecules in a container is zero

[joe1joe1joe2]

Hey there guys i am new here and not sure if this is in the right section, well here goes.


Just doing some revision and realized I must have been asleep for the Kinetic theory lessons, i have now grasped some of the basics, but have come to this question and not usre how to answer it...

Explain why the average velocity of the gas molecules in a container is zero.

Now i have had a look around on wikipedia and things like that but it goes into a lot of detail, and we don't need to go into that much detail, also I don't just want the answer handed to me i would appreciate it if you could explain it for me in fairly simple terms...


Many Thanks


Joe

 

[Doc Al]

Hint: What's the difference between velocity and speed?

 

[joe1joe1joe2]

velocity is a vector quantity and therefore has a direction as well as the speed...

so because this is the mean square velocity, does that mean as the molecules are boucing off the walls all the time then their velocities are cancelling each other out because as it hits at 500m/s it then rebounds at -500m/s or something along those lines?

ooo wait squaring it, that will change it from being negative to postive...

 

[Doc Al]

so because this is the mean square velocity...

Who said anything about squaring?