1. Does a 2-kilogram bar of gold have twice as much inertia as a 1-kilogram bar of gold? Twice as much mass? Twice as much volume? Twice as much weight when weighed in the same location?
2. Does a 2-kilogram bar of gold have twice as much inertia as a 1-kilogram bunch of bananas? Twice as much mass? Twice as much volume? Twice as much weight when weighed in the same location?
3. How does the mass of a bar of gold vary with location?
1. The answer is yes to all questions. A 2-kilogram bar of gold has twice as many gold atoms, and therefore twice the amount of matter, mass, and weight. The bars consist of the same material, so the 2-kilogram bar also has twice the volume.
2. Two kilograms of anything has twice the inertia and twice the mass of one kilogram of anything else. Since mass and weight are proportional in the same location, two kilograms of anything will weigh twice as much as one kilogram of anything. Except for volume, the answer to all the questions is yes. Volume and mass are proportional only when the materials are identical—when they have the same density. (Density is mass/volume). Gold is much more dense than bananas, so two kilograms of gold must occupy less volume than one kilogram of bananas.
3. Not at all! It consists of the same number of atoms no matter what the location. Although its weight may vary with location, it has the same mass everywhere. This is why mass is preferred to weight in scientific studies.