Pearson Edexcel International GCSE Science Single Award 10: Physics: Forces and motion

Topic 1 connects motion graphs to forces and road safety. These notes follow only the Science Single Award points in Pearson 4SS0 Issue 4. Scalars and vectors, resultant-force diagrams, terminal velocity, momentum and moments belong to broader routes and are excluded.

Describing motion

Average speed is distance moved divided by time:

$$v=\frac{d}{t}$$

Use metres, seconds and metres per second unless a conversion is required. Average speed describes the whole interval and need not equal the speed at every instant.

A distance-time graph shows accumulated distance. Its gradient is speed. A straight rising line means constant speed, a horizontal line means stationary, and a curve that becomes steeper means increasing speed. Because distance does not decrease, a standard distance-time graph should not slope downward.

Acceleration is change in velocity per unit time:

$$a=\frac{v-u}{t}$$