The person will have a mass of 49.895 kg on earth. The person will have a mass of 49.895 kg on the moon. For earth, simply convert lbs to kg by multiplying by 0.453592, Giving. 110 lb * 0.453592 kg/lb = 49.89512 kg So the mass of a 110 lb person on earth is 49.895 kg. And on the moon, the mass of that same person will also be 49.895 kg. Remember, mass is not the same as weight.