A car covers the first half of the distance between two places at 40 km h⁻¹ and the other half at 60 km h⁻¹. The average speed of the car is:
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Question

A car covers the first half of the distance between two places at 40 km h⁻¹ and the other half at 60 km h⁻¹. The average speed of the car is:

G1 Physics · Accepted Answer

Step 1: For equal distances at speeds u and v, average speed is the harmonic mean 2uv/(u+v). Step 2: Substitute 40 and 60 km h⁻¹: 2×40×60/(40+60)=4800/100=48 km h⁻¹. Final answer: B.