Mass measures the amount of matter and is measured in kilograms; weight is gravitational force in newtons. Use W = mg with gravitational field strength g in N/kg. Mass stays the same when an object moves to another gravitational field, but its weight can change. Example: A 5 kg object moves from g = 10 N/kg to g = 2 N/kg. State its new mass and weight. Mass remains 5 kg; weight = 5 × 2 = 10 N. A correct answer needs an appropriate unit as well as a numerical value. Use evidence. Apply the model.