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Question
Calculate the speed of a car that travels 150 metres in 10 seconds. Express your answer in km/h.
🔗 Concept: 8.3 Speed
Speed = 150 m ÷ 10 s — express the answer in km/h.
![Question 1 - Calculate the speed - Measurement of Time an - [Teachoo] - Questions at the end of the chapter](https://cdn.teachoo.com/test/c107f371-8674-4e64-8572-3613c13003db/image-a-car-on-a-straight-road-with-a-150-m-distance-marker-and-a-stopwatch-at-10-seconds-ready-to-calculate-speed.png)
Show Answer
Speed = 15 m/s = 54 km/h
Explanation
📋 Given
- Distance = 150 m
- Time = 10 s
🔄 Unit Conversion
- Units are already m and s → answer in m/s first.
- To convert m/s to km/h: multiply by 3.6.
- Why: 1 km = 1000 m & 1 h = 3600 s, so 1 km/h = 1000/3600 m/s = 1/3.6 m/s.
📐 Formula
Speed = Distance ÷ Time
Step 1 — Find speed in m/s
$$\text{Speed} = \frac{150 \text{ m}}{10 \text{ s}} = 15 \text{ m/s}$$
Step 2 — Convert to km/h
Multiply by 3.6 (since 1 m/s = 3.6 km/h).
$$15 \times 3.6 = \boxed{54 \text{ km/h}}$$
Speed = 15 m/s = 54 km/h — multiply m/s by 3.6 to convert.
