The square root of `overline(v^2)` is called the root-mean-square speed. Example: What is the rms speed of air molecules (`O_2` and `N_2`) at room temperature (20°C)? Given: `T = 20°C = 293\ K` Equation: `v_(rms) = sqrt((3kT)/m)` Solution: For `O_2`, The molecular mass `O_2` is `32\ u` and `1\ u = 1.66times10^(-27)\ kg` `m_(O_2) = (32)(1.66times10^(-27)\ kg) = 5.3 times 10^(-26)\ kg` `v_(rms) = sqrt((3(1.38times10^(-23)\ J//K)(293\ K))/(5.3times10^(-26)\ kg)) = 480\ m//s` For `N_2`, The molecular mass `N_2` is `28\ u` and `1\ u = 1.66times10^(-27)\ kg` `m_(O_2) = (28)(1.66times10^(-27)\ kg) = 4.6 times 10^(-26)\ kg` `v_(rms) = sqrt((3(1.38times10^(-23)\ J//K)(293\ K))/(4.6times10^(-26)\ kg)) = 510\ m//s`