weight
The amount of inertia an object has is simply related to the mass of the object. Mass and Weight are two different things. Mass typically in units of kg or grams is basically a measure of what comprises an object. Weight is the measure of how much the force of gravity is pulling on you. In fact, instead of saying 'I weigh 80 lb. ', one could say that 'the force of gravity is pulling on me with a force of 80 lb. ' The metric unit for weight and force is the Newton.