Motion quantities and graphs
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 1 worked example, 5 practice questions, 2 real past-paper questions with the answers explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Describing motion exactly
- Four definitions
Read the transcript of the teaching part
Last time
Before we start: last time, in Uniform acceleration, free fall and projectiles, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Describing motion exactly
A car goes round a bend at a steady fifty kilometres per hour. Its speed never changes, yet we say it is accelerating. To see why, we need exact definitions, and then graphs that show them.
Four definitions
Displacement is the distance in a straight line from the starting point, in a stated direction. Speed is the distance travelled per unit time. Velocity is the rate of change of displacement. Acceleration is the rate of change of velocity. Speed is a scalar. Velocity, displacement and acceleration are vectors.
How often it comes up
How often Cambridge has asked each part, counted by ExamYard from every past paper in its question bank: Area under a velocity–time graph · Motion graphs · Projectile motion · What a physical quantity is.
The whole chapter: Kinematics, Physical Quantities and Units, Kinematics.
Chapter 2.1: Kinematics
- Motion quantities and graphs 4 min
Also for A Level Physics 9702
Which topics come up most in A Level Physics 9702 past papers, counted from every paper since 2004: Paper 1 topic frequency, Paper 2 topic frequency.