Scalars, vectors and resultants
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 1 worked example, 9 practice questions, 1 real past-paper question with the answer explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Size is not enough
- Scalars and vectors
- Which kind is it?
Read the transcript of the teaching part
Size is not enough
Imagine I tell you a car is travelling at twenty metres per second. Is that enough? It matters a great deal whether it is going north, or straight at a wall. Some quantities need a direction as well as a size.
Scalars and vectors
A scalar is a quantity that has size only. Mass, time and energy are scalars. A vector is a quantity that has both size and direction. Force, weight, velocity and acceleration are all vectors, so we must say which way they point. A vector is written with its direction: for example, fifteen metres per second due north.
Which kind is it?
Here are the pairs to learn. On the left, the scalars: distance, speed, mass, time and energy. On the right, the vectors: displacement, velocity, weight, force and acceleration. Notice that speed and velocity are a pair, and so are distance and displacement.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Scalars, vectors and resultants · Resultant of two vectors · Scalars and vectors.
The whole chapter: Physical Quantities and Measurement Techniques, Physical Quantities and Measurement Techniques.
Chapter 1.1: Physical quantities
- Scalars, vectors and resultants 5 min
Also for O Level Physics 5054
Which topics come up most in O Level Physics 5054 past papers, counted from every paper since 2004.