Speed Conversions
- m/s to km/h: multiply by 3.6
- km/h to m/s: divide by 3.6
- m/s to mph: multiply by 2.24
- mph to m/s: divide by 2.24
Common Unit Conversions
| From | To | Method |
|---|---|---|
| g/cm³ | kg/m³ | × 1000 |
| kg/m³ | g/cm³ | ÷ 1000 |
| cm³ | m³ | ÷ 1,000,000 |
| cm² | m² | ÷ 10,000 |
This deep dive covers Mastering Unit Conversions within Compound Measures for GCSE Mathematics. Revise Compound Measures in Number for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 4 of 8 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Compound Measures
Which formula correctly gives speed in terms of distance and time?
A car travels 80 km at 40 km/h and then 80 km at 80 km/h. Explain why the average speed for the whole journey is NOT 60 km/h.
Quick recall flashcards
Convert 72 km/h to m/s
Divide by 3.6
72 ÷ 3.6 = 20 m/s
Check: 72 km/h means 72000 m per 3600 s
72000 ÷ 3600 = 20 m/s
Convert 25 m/s to km/h
Multiply by 3.6
25 × 3.6 = 90 km/h
Check: 25 m/s means 25 metres per second
25 × 3600 ÷ 1000 = 90 km/h