Mass and weight · revision map · IGCSE 0625, Topic 1.3
TOPIC 1.3 · MASS AND WEIGHT
CAMBRIDGE IGCSE PHYSICS 0625 · ONE-PAGE REVISION MAP
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MASS &
WEIGHT1.3
WEIGHT1.3
Mass
Mass is the amount of matter in an object.
- Measured in kilograms (kg) with a balance.
- The same everywhere, on Earth or the Moon.
- More mass means more resistance to a change in motion. We call this inertia.
Weight
Weight is the gravitational force pulling on a mass.
W = m gweight = mass × gravitational field strength
- Measured in newtons (N).
- Changes if gravity changes with location.
- Weight always acts downward.
Gravitational Field Strength
g is the gravitational force on each kilogram.
g = W / m
unit: newtons per
kilogram (N/kg)
kilogram (N/kg)
The same mass weighs less where g is smaller:
on Earth
g ≈ 9.8 N/kg
g ≈ 9.8 N/kg
on the Moon
g ≈ 1.6 N/kg
g ≈ 1.6 N/kg
Mass vs Weight
MASS
- amount of matter
- scalar quantity
- unit: kilogram (kg)
- stays constant
- found with a balance
WEIGHT
- force of gravity
- vector quantity
- unit: newton (N)
- varies with g
- found from W = mg