v_{m} = (3KT/m)^{1/2}

Mass of N_{2} = 28.013/(6.022 x 10^{23}) = 4.6517 x 10^{-23}g

M = 4.65 x 10^{-26}kg

Temperature T = - 240 + 273 = + 33 K

v_{m} = ((3 x 1.38 x 10^{-23} x 33)/(4.65 x 10^{-26})^{1/2} = (29.380 x 10^{3})^{1/2}

v_{m} = 171.39m/s = 0.171km/s

6v_{m} = 1.028km/s