If a train is travelling eastward with a constant velocity of 15 m/s, there is no net force acting on the train.
Answer: Option B
Explanation:
According to Newton 2nd law, the external force is proportionate to the rates of change of momentum which states that force will be indirectly proportional to the rates of variation in velocity. So, as the velocity is constant for the train, the rate of variation in velocity or the acceleration will be zero. Thus the total external forces acting on the train will be zero. But the train will be moving continuously due to the energy obtained from the engine.