At what temperature the mean speed of the molecules of hydrogen gas equals the escape speed from the earth?

Explanation

Mean speed of the molecule `=(sqrt(8RT)/(pi M))`
Escape velocity =(sqrt(2 gr))`
` (sqrt(8RT))/(sqrt(pi M))= (sqrt(2gr))`
` rArr (8RT)/(piM)= 2gr`
` rArr T = 2gr ((piM)/8R)`
` = (2 xx 98 xx 6400000 xx 3.14 xx 2 xx 10)/(8 xx 8.3)`
`=11863.9 =11800 m/s`