UCSB Science Line
 Why a mass of 1 kilogram will have a different weight on the moon? Question Date: 2013-01-13 Answer 1:The mass of on an object is basically the amount of "stuff" (or more properly, the amount of matter) in that object. Technically a kilogram is a unit of mass, not weight. Weight is the force experienced by that object due to the acceleration of gravity. Force is equal to mass times acceleration (F=m*a) and is measured in newtons (1 newton = 1 kg*m/s2). On EarthÂ´s surface the acceleration is due to gravity is 9.8 m/s2. So an object with a mass of 1 kilogram has a weight of 9.8 newtons. The acceleration due to gravity on a given planet depends on the mass and radius of that planet. (Specifically, g=GM/r2, where g is acceleration due to gravity, G is a universal gravitation constant, M is the mass of the planet, and r is the radius of the planet.) Because the Moon has less mass than the Earth, gravitational acceleration (and hence, weight) is less on the Moon than on Earth. Click Here to return to the search form.