Physics

Problem

A train moves

150\,\text{km}

east at

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

and then

90\,\text{km}

west at

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

. What is the difference between its average speed and the magnitude of its average velocity for the whole motion? a)

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

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

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

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