Physics

Problem

Which pair of speeds represents nearly the same magnitude? a)

18\,\text{km h}^{-1}

and

6\,\text{m s}^{-1}

30\,\text{km h}^{-1}

and

10\,\text{m s}^{-1}

36\,\text{km h}^{-1}

and

10\,\text{m s}^{-1}

60\,\text{km h}^{-1}

and

15\,\text{m s}^{-1}

Intuitive explanation

This problem is testing whether you can recognize that speed is a scalar—it has only magnitude, no direction. The key insight is to convert all speeds to the same units and compare their numerical values directly. Don't get distracted by different directions or reference frames; focus purely on how fast each object is moving, regardless of where it's going.

Intuitive explanation

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