vm = (3KT/m)1/2
Mass of a methane molecule = 16.043/(6.022 x 1023)
= 2.664 x 10-26kg
vm = ((3 x 1.38 x 10-23 x 37)/(2.664 x 10-26))1/2 = (57.5 x 103)1/2
vm = 239.7m/s = 0.239km/s
6 × vm = 1.438 km/s
ve = 0.630 km/s
Methane can escape from Charon because 6 × vm = 1.438 km/s is greater than the escape velocity (ve = 0.630km/s).