Railway tracks are banked on curves A. necessary centrifugal force may be obtained from the horizontal component weight of the train B. to avoid frictional force between the tracks and wheels C. necessary centripetal force may be obtained from the horizontal component of the weight of the train D. the train may not fly off in the opposite direction

The correct answer is: C. necessary centripetal force may be obtained from the horizontal component of the weight of the train.

When a train goes around a curve, it experiences a centripetal force that pulls it towards the center of the curve. This force is provided by the friction between the wheels and the tracks. However, if the curve is too sharp, the frictional force may not be enough to keep the train from derailing. In this case, the tracks can be banked, or tilted, so that the horizontal component of the train’s weight provides some of the centripetal force. This reduces the amount of frictional force required, and makes it safer for the train to travel around the curve.

Option A is incorrect because the horizontal component of the train’s weight is not enough to provide the necessary centripetal force for a sharp curve. Option B is incorrect because frictional force is still required to keep the train from derailing, even on banked tracks. Option D is incorrect because the train is not in danger of flying off in the opposite direction.