Physics

Problem

A locomotive of mass

4.0\times10^{5}\,\text{kg}

pulls a freight wagon of mass

8.0\times10^{4}\,\text{kg}

on a level track. Neglect all resistive forces. (i) If the traction force exerted by the locomotive on the track is

1.2\times10^{5}\,\text{N}

, determine the common acceleration of the locomotive–wagon system. (ii) Starting from rest, how much time will the system take to reach a speed of

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

under this constant force? (iii) On a parallel road, a motorcycle–rider system of total mass

2.0\times10^{2}\,\text{kg}

experiences a net forward force of

5.0\times10^{2}\,\text{N}

. Calculate the time this system would take to reach the same speed of

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

when starting from rest. (iv) Compare the times obtained in parts (ii) and (iii) and comment on how the difference illustrates the concept of inertia.

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