If earths mass were reduced by 1/2 , but its radious satyed the same , how much would your weight change ? Would it also be reduced by half ?
As you have probably discovered, using the formula
F = GmM/r^2 will help out. If you have a new mass, generating weight
N = Gm(M/2)/r^2, then N = (1/2) * GmM/r^2) = 1/2 F