An athlete runs 100 m in 10 s and then another 50 m in 5 s. Wh... | General Science MCQ | Examoogle

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General SciencePhysics: Motion

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An athlete runs 100 m in 10 s and then another 50 m in 5 s. What is the average speed of the athlete?

10 m/s

15 m/s

5 m/s

20 m/s

Correct Answer

🔬 SC • Science Concept & PrincipleGeneral SciencePhysics: Motion

Option A

10 m/s

Quick Summary:

Average speed is calculated by dividing the total distance traveled by the total time taken. For this athlete, the total distance is $100\text{ m} + 50\text{ m} = 150\text{ m}$ , and the total time is $10\text{ s} + 5\text{ s} = 15\text{ s}$ .

🔬SCScience SolutionConcept & Principle

💡 Explanation

💡 Everyday Analogy (Real-World Intuition)

Think of a road trip: even if you drive faster on a highway and slower through a town, your average speed is simply the total distance on the odometer divided by the total time spent driving.

🧠 Memory Mnemonic / Shortcut Aid

Total Trip / Total Time (T3 Rule)

🔢 Key Formulas

$\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}}$

$v_{avg} = \frac{d_1 + d_2}{t_1 + t_2}$

⚙️ Working Principle

The principle of uniform motion assumes that for varying segments of a journey, the overall efficiency is represented by the average speed. Mathematically, it is the ratio of the total path length covered to the elapsed time interval, independent of changes in instantaneous velocity.

📌 Key Points

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Average speed is a scalar quantity.
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It does not represent the instantaneous speed at any specific moment.
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The unit for average speed in the SI system is $m/s$ .

✅ Advantages

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Provides a simple metric to compare overall journey efficiency.
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Useful for calculating estimated time of arrival (ETA).

❌ Disadvantages / Limitations

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Does not account for variations or pauses during the journey.
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Cannot determine the direction of motion (unlike velocity).

🛠️ Applications / Uses

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Calculating vehicle fuel efficiency over long distances.
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Determining athlete performance in track and field events.

📄 Additional Information

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Total Distance = $150\text{ m}$ . Total Time = $15\text{ s}$ . Result = $150/15 = 10\text{ m/s}$ .
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Option B is calculated by incorrectly using $150/10$ or similar errors. Option C is $75/15$ . Option D is a miscalculation of individual segments.

📊 Diagram / Illustration

✅

A is correct — The total distance of $150\text{ m}$ divided by the total duration of $15\text{ s}$ yields exactly $10\text{ m/s}$ .

Core Concepts Used

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Scalar Quantities Kinematics Rate of Change

💡 EXAM TIP

Always sum total distance and total time before dividing; never average the individual speeds unless the time intervals are identical.

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