A locomotive of mass pulls a freight wagon of mass on a level track

PHYSICS · Subjective · CBSE · Physics · Laws of Motion · Laws of Motion

Problem

A locomotive of mass 4.0×105 kg4.0\times10^{5}\,\text{kg} pulls a freight wagon of mass 8.0×104 kg8.0\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 1.2×105 N1.2\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 km h−154\,\text{km\,h}^{-1} under this constant force? (iii) On a parallel road, a motorcycle–rider system of total mass 2.0×102 kg2.0\times10^{2}\,\text{kg} experiences a net forward force of 5.0×102 N5.0\times10^{2}\,\text{N}. Calculate the time this system would take to reach the same speed of 54 km h−154\,\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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