Hey,(adsbygoogle = window.adsbygoogle || []).push({});

This should be a pretty simple problem to answer... I'm just a bit confused on this, and want to make sure I'm right. It's an easy problem:

Molecules in a gas can only move in the x direction (i.e., [tex]v_{y}=v_{z}=0)[/tex]. You set up an experiment in which you measure the velocity of a few molecules and the result that you obtain is the following (expressed in m/s):

2, -4, 6, 1, -3, -2, -5, 2, -1, 4, 3, -5

Calculate: a) the average x-component of the velocity [tex](v_{x})_{av}[/tex], b) the average speed [tex](v)_{av}[/tex], and c) the root mean square of the velocity [tex]v_{rms}[/tex]

For a), the x-component of velocity is literally just the average, right? No absolute values b/c we're not talking about speed here.

For b) because I'm being asked for the averagespeed, here is where I take the absolute values of all of these and average them together, right?

For c) This is where I'm most confused... Here, wouldn't I just square what I got for b) and then take the square root of it? That seems to make absolutley no sense. Would I then use the formula below?

I noticed something in the book: [tex](v_{x}^2)_{av}, (v_{y}^2)_{av}, (v_{z}^2)_{av}[/tex] must all beequal. Hence: [tex](v_{x}^2)_{av} = \displaystyle{\frac{1}{3}}(v^2)_{av}[/tex]

This wouldn't apply for this situation, correct? As the y and the z components are 0, right?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Kinetic-Molecular Model of Ideal Gas: vrms/vav

**Physics Forums | Science Articles, Homework Help, Discussion**