Maxwel distribution

  • #1
114
0

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!

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
Doc Al
Mentor
45,092
1,397
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.
 
  • #3
malawi_glenn
Science Advisor
Homework Helper
4,786
22
what do you mean by "squaring all values"?

Do you weight all speed^2 with their occurence?
 
  • #4
114
0
so the average of the squares of the speeds was 6.6885*10^5
 
  • #5
114
0
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
 
  • #6
malawi_glenn
Science Advisor
Homework Helper
4,786
22
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
 
  • #7
114
0
square root { (3kT) /m}

is that the weighted average?
 

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