The ratio of the mass of the moon to that of the earth is 1:81. If the radius of the moon is assumed to be one-fourth of that of the earth , then what is the acceleration due to gravity on the surface of the moon in terms of that on the earth's surface ? Hence, find the escape velocity from the surface of the moon in terms of that from the earth's surface.

Answer

`g_m=0.198g_e,v_m^(esc)=1/2v_e^(esc)`