Mass and Weight
Mass is the amount of matter (kg); weight is the force due to gravity, W = mg (N).
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Mass vs weight
Mass is a scalar measure of the amount of matter; SI unit is the kilogram (kg). Weight is the force exerted on a body by gravity: W = mg. Weight is a vector (direction: toward the centre of the attracting body). On the Moon, mass is the same but weight is less because g is smaller.
✔ Key takeaway: Mass is intrinsic; weight W = mg depends on g.
💭 Think about this:
Why do we say "weigh" in kg in everyday life when kg is mass?