Train Motion: Does it Really Move While Rotating Wheels?

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In summary, the train does move despite the conflicting directions of the top and bottom points of the wheel. The key is that the center of the wheel, which represents the overall movement of the train, is moving at the same speed as the train itself. Therefore, the train moves west at a speed of 50 km/hr.
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A train is moving west at 50 km/hr. In relationship to the tracks, the top point of the trains wheel is also moving east. However, the bottom point of the wheel is moving west. Assuming the wheel rotates at a constant speed, does the train really move at all?
 
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If the train is moving west then the top of a wheel is also traveling west but at twice the speed of the train. The bottom point of the wheel is moving neither west nor east unless it is sliding on the track. Of course, the center of the wheel is moving west at exactly the same speed as the train.

I can assure you that the train does move! :)
 
  • #3
What Tide said, plus:

If the top of the wheel is moving east and the bottom is moving west, then no, the train does not move; it just sits there spinning its wheels. This of course assumes that the westbound velocity at the bottom and the eastbound velocity at the top are equal. If they're not equal, then the train moves at a rate equal to the difference of the two.
 

FAQ: Train Motion: Does it Really Move While Rotating Wheels?

What causes a train to move while its wheels are rotating?

The movement of a train is caused by the rotational force of its wheels against the tracks. This rotational force, also known as torque, propels the train forward.

Is it possible for a train to move without its wheels rotating?

No, in order for a train to move, its wheels must rotate. The rotation of the wheels creates the necessary force to move the train forward.

Does the speed of the train affect the rotation of its wheels?

Yes, the speed of the train can affect the rotation of its wheels. The faster the train moves, the faster its wheels will rotate. However, the rotation of the wheels also depends on other factors such as the weight of the train and the condition of the tracks.

Why do trains have multiple sets of wheels?

Trains have multiple sets of wheels to distribute the weight of the train evenly and to increase their stability. This allows the train to move smoothly and efficiently along the tracks without causing damage to the wheels or the tracks.

How does the rotation of the wheels affect the train's direction?

The rotation of the wheels is what allows the train to change direction. By rotating the wheels on one side faster than the other, the train can turn and follow the curvature of the tracks. This is similar to how a car turns using its front wheels.

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