What is the difference between mass and weight? Why does weight change on the moon?
I always thought mass and weight were the same thing. My teacher corrected me and said they are different. If I weigh 60 kg on Earth, what would I weigh on the moon?
1 Answer
Mass: amount of matter in an object. Measured in kg. Does NOT change with location. Weight: force exerted on an object due to gravity. W = m*g. Measured in Newtons. CHANGES with gravity. On Earth: g = 9.8 m/s^2 (about 10). On Moon: g = 1.63 m/s^2 (about 1/6th of Earth). Your mass = 60 kg everywhere. Your weight on Earth = 60 * 10 = 600 N. Your weight on Moon = 60 * 1.63 = 97.8 N (roughly 100 N, or 1/6th of Earth weight). When people say "I weigh 60 kg" they actually mean their MASS is 60 kg. Technically weight should be in Newtons. In space with no gravity: weight = 0 but mass remains 60 kg.
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