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Question
A car covers 60 km in the first hour, 70 km in the second hour, and 50 km in the third hour. Is the motion uniform? Justify your answer. Find the average speed of the car.
🔗 Concepts: 8.4 Uniform and Non-uniform Linear Motion | 8.3 Speed
Car: 60 km, 70 km, 50 km in 3 hours — is the motion uniform?
![Question 8 - A car covers 60 km - Measurement of Time an - [Teachoo] - Questions at the end of the chapter](https://cdn.teachoo.com/test/a101d818-ed8f-447c-9f2f-d1c57fa7f23b/image-a-car-odometer-showing-60-km-in-hour-1-70-km-in-hour-2-and-50-km-in-hour-3.png)
Show Answer
Non-uniform motion — average speed = 60 km/h
Explanation
📋 Given
- Hour 1: 60 km covered
- Hour 2: 70 km covered
- Hour 3: 50 km covered
- Total time = 3 h
🔄 Unit Conversion
- No conversion needed — all distances in km, time in h.
- Answer will be in km/h.
📐 Formula
Average Speed = Total Distance ÷ Total Time
Step 1 — Check if motion is uniform
Distances in equal intervals: 60, 70, 50 km → all different.
Unequal distances → Non-uniform motion .
Step 2 — Find total distance
$$\text{Total distance} = 60 + 70 + 50 = 180 \text{ km}$$
Step 3 — Calculate average speed
$$\text{Average speed} = \frac{180 \text{ km}}{3 \text{ h}} = \boxed{60 \text{ km/h}}$$
Non-uniform (distances differ each hour) — average speed = 60 km/h.
