We examine the generation of gravity waves by the surface convection zone of low-mass main sequence stars with solar metallicity .
It is found that the total momentum luminosity in waves rises with stellar mass , up to the quasi-disappearance of the convection zone around 6500 K ( corresponding to a mass of \sim 1.4 M _ { \odot } for solar metallicity ) where the luminosity drastically drops .
We calculate the net momentum extraction associated with these waves and explain how the calculated mass dependence helps resolve the enigma of the Li dip in terms of rotational mixing , forming a coherent picture of mixing in all main sequence stars .