This key facts covers Weight vs Mass within Forces & Their Effects for GCSE Physics. Revise Forces & Their Effects in Forces for GCSE Physics with 28 exam-style questions and 11 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 3 of 13 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
⚖️ Weight vs Mass
MASS (m):
- Amount of matter in an object
- Measured in kilograms (kg)
- SAME everywhere in the universe
- Scalar quantity (magnitude only)
WEIGHT (W):
- Force of gravity acting on an object
- Measured in Newtons (N)
- DIFFERENT on different planets
- Vector quantity (magnitude AND direction)
W = m × g
Weight (N) = mass (kg) × gravitational field strength (N/kg)
Example: A 70 kg person:
- On Earth (g = 10): W = 70 × 10 = 700 N
- On Moon (g = 1.6): W = 70 × 1.6 = 112 N
- Mass stays 70 kg in both places!
Practice questions for Forces & Their Effects
What is a force?
Explain what is meant by the resultant force on an object.
Quick recall flashcards
Resultant Force
Same direction: ADD them
Resultant Force
Opposite directions: SUBTRACT (bigger − smaller)