# Maxwel distribution

itryphysics

## Homework Statement

A gas consisting of 15,200 molecules, each of mass 2.00×10^−26 kg , has the following distribution of speeds, which crudely mimics the Maxwell distribution:
Number of Molecules
1600
4100
4700
3100
1300
400
Speed
210
420
630
840
1050
1260

Determine Vrms for this distribution of speeds.
Given your value for Vrms , what (effective) temperature would you assign to this gas?

## Homework Equations

Vrms = square root {Average V^2} or square root {3kT/m}

## The Attempt at a Solution

So I squared all the values and then divided by the total number to obrain (Average velocity^2) and then took the square root ...the attempt failed..many thanks to anyone who helps!

## Answers and Replies

Mentor
So I squared all the values and then divided by the total number to obrain (Average velocity^2) and then took the square root ...the attempt failed..
You need to first find the weighted average of the squares of the speeds.

Homework Helper
Gold Member
what do you mean by "squaring all values"?

Do you weight all speed^2 with their occurence?

itryphysics
so the average of the squares of the speeds was 6.6885*10^5

itryphysics
what do you mean by "squaring all values"?

Do you weight all speed^2 with their occurence?

sorry for the confusion...i meant squaring all speeds..

and I dont know wht you mean by your second question :S

Homework Helper
Gold Member
sorry for the confusion...i meant squaring all speeds..

and I dont know wht you mean by your second question :S

then you did not do the weigted average.. look it up

itryphysics
square root { (3kT) /m}

is that the weighted average?