Cambridge IGCSE Physics Notes 1.2: Motion
Cambridge IGCSE Physics notes on speed, velocity, acceleration, distance-time graphs, speed-time graphs, free fall, and terminal velocity.
Q: What does Cambridge IGCSE Physics Notes 1.2: Motion cover?
A: It follows official Cambridge Physics section 1.2 for syllabuses 0625 and 0972, with Core ideas separated from Supplement depth.
Motion questions translate between words, equations, and graphs. Gradient describes a rate of change, while area under a speed-time graph gives distance travelled.
The ideas that organise this section
- Speed is distance travelled per unit time; velocity also includes direction.
- The gradient of a distance-time graph gives speed, and the gradient of a speed-time graph gives acceleration.
- Terminal velocity occurs when drag balances weight so resultant force and acceleration are zero.
Core route
Core candidates should be ready to describe, calculate, interpret, and apply the following:
- Calculate speed and average speed and interpret distance-time and speed-time graphs.
- Use the area under a speed-time graph for constant-speed or constant-acceleration motion.
- Recall that gravitational acceleration near Earth's surface is approximately constant.
Supplement route
Extended candidates study all Core content and add the following depth:
- Calculate acceleration from velocity change and graph gradient.
- Describe free fall with and without resistance, including terminal velocity.
- Use negative acceleration consistently when velocity decreases in the chosen positive direction.
Formula route
- Relationship: speed = distance / time.
- Relationship: acceleration = change in velocity / time.
Write the relationship before substituting. Convert units first, keep extra figures during working, and round only the final answer to sensible precision.
Build a connected model
In Motion, a strong answer connects the named quantity or model to observable evidence. Begin by defining the physical quantity in words or with its relationship. Identify which values are scalars and which require a direction. Represent the situation with a labelled diagram, graph, field pattern, ray or circuit when that makes the relationship visible. The representation is part of the reasoning: its labels, arrows and scale should agree with the written explanation.
For a calculation, write the governing relationship before substitution, convert prefixes and time units, keep unrounded values during working and attach the correct final unit. For a qualitative question, use a cause-link-consequence chain. Name what changes, state the physical mechanism that links the change to the system, and then give the measurable result. If two cases are compared, hold unrelated variables constant and use the same physical principle for both.
