Most of the energy of train systems is used in starting and stopping. The design of the rotating train platform saves energy, because passengers can board or leave a train while the train is still moving. Study the sketch and convince yourself that this is true. The small circular platform in the middle is stationary, and is connected to a stationary stairway. a. If there is to be no relative motion between the train and the edge of the platform, how fast must the train move compared to the rim speed of the rotating platform?
b. Why is the stairway located at the center of the platform?