Question 5 of 11intermediate🔧 ApplyNumerical3 marks

The fastest galloping horse can reach the speed of approximately 18 m/s. How does this compare to the speed of a train moving at 72 km/h?

Correct Answer

Speeds can be compared by converting them to the same unit. To compare 18 m/s with 72 km/h, either convert m/s to km/h or km/h to m/s.

The conversion relationship is: 1 km/h = 1000 m/3600 s = 5/18 m/s.

Converting the train's speed from km/h to m/s: 72 km/h = 72 × (1000 m / 3600 s) = 72 × (5/18) = 20 m/s.

Comparing the speeds: Horse = 18 m/s, Train = 20 m/s.

The difference is: 20 m/s - 18 m/s = 2 m/s.

Alternatively, convert the horse's speed to km/h: 18 m/s = 18×3.618 \times 3.6 = 64.8 km/h.

The train is faster than the horse. The train's speed is 20 m/s while the horse's speed is 18 m/s. The train is faster by 2 m/s (or 7.2 km/h).

Exercise: Let Us Enhance Our Learning | Q: 5 | (Page Page 14)
For More Understanding

Explanation

The chapter explains that speeds can be compared by converting them to the same unit. To compare 18 m/s with 72 km/h, either convert m/s to km/h or km/h to m/s. The chapter provides the conversion: 1 km/h = 1000 m/3600 s = 5/18 m/s.

Solution Steps

  1. Step 1: Convert train's speed from km/h to m/s: 72 km/h = 72 × (1000 m / 3600 s) = 72 × (5/18) = 20 m/s

  2. Step 2: Compare speeds: Horse = 18 m/s, Train = 20 m/s

  3. Step 3: Calculate difference: 20 m/s - 18 m/s = 2 m/s

  4. Step 4: Alternative: Convert horse speed to km/h: 18 m/s = 18×3.618 \times 3.6 = 64.8 km/h

  5. Step 5: Final answer: Train is faster by 2 m/s (or 7.2 km/h)

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