1. Tardigrade
  2. Question
  3. Physics
  4. Velocities of four gas molecules are 2,3,-4,-1 m / sec respectively. Then choose the correct statements I. the mean velocity of molecules is zero II. the mean speed of molecules is 2.5 m / s III. the mean square velocity of molecules is 7.5 m 2 / s 2 IV. the root mean square velocity of molecules is 2.74 m / s

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Q. Velocities of four gas molecules are $2,3,-4,-1\, m / sec$ respectively.
Then choose the correct statements
I. the mean velocity of molecules is zero
II. the mean speed of molecules is $2.5\, m / s$
III. the mean square velocity of molecules is $7.5 \,m ^2 / s ^2$
IV. the root mean square velocity of molecules is $2.74\, m / s$

Kinetic Theory

Solution:

Mean velocity $=\frac{2+3-4-1}{4}=0$,
Mean speed $=\frac{2+3+4+1}{4}=2.5$,
Mean square speed $=\frac{2^2+3^2+4^2+1^2}{4}=7.5 \,m ^2 / s ^2$,
$V_{ rms }=\sqrt{7.5}=2.74\,m / s$