Average Speed for Equal Distances – Rankers Physics

Average Speed and Velocity: Practice Problem & Solution

A vehicle travels half of the total distance with speed 2 m/s and the other half with speed 5 m/s, then its average speed is
\[\frac{7}{2}\text{ m/s}\]
\[\frac{20}{7}\text{ m/s}\]
\[\frac{14}{3}\text{ m/s}\]
\[\frac{7}{20}\text{ m/s}\]

Solution Explained:

To solve this problem, we apply the core principles of Average Speed and Velocity. Understanding the underlying formula is key to arriving at the correct answer below:

Formula: For equal halves of distance, the average speed is the harmonic mean: \(v_{av} = \frac{2v_1v_2}{v_1+v_2}\). Putting values, \(v_{av} = \frac{2 \times 2 \times 5}{2+5} = \frac{20}{7}\text{ m/s}\).

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