# Maxwel distribution

## 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

Doc Al
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.

malawi_glenn
Science Advisor
Homework Helper
what do you mean by "squaring all values"?

Do you weight all speed^2 with their occurence?

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

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

malawi_glenn
Science Advisor
Homework Helper
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

square root { (3kT) /m}

is that the weighted average?