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Momentum question. Acceleration on a moving track

  1. Feb 14, 2016 #1

    I've a question that is baffling me a little.

    If a train was made so that it would act as a moving track / roadway and the cars were connected so as to complete a length of the track, in an oval for example. Say we accelerate the moving trackway to 100 Mph, and then a car accelerates to 100mph. Total speed = 200mph.

    Now say you have a moving track on top of the railway track. Are all of the speeds combined, is it even possible? Would I imagine it would be like running on a travelator? So long as you joined the train at 100mph would you instantly accelerate to 200 mph?
    It is hurting my brain and I know something in my thinking is incorrect!
  2. jcsd
  3. Feb 14, 2016 #2


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    Science Advisor
    Gold Member

    How did that "instantly" come into this?
  4. Feb 14, 2016 #3
    Ah yes I see now,

    But once on the train you could then accelerate the vehicle and go 200mph....
  5. Feb 14, 2016 #4

    Doc Al

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    Staff: Mentor

    I assume you mean something like this: Say a train is moving at 100 mph East with respect to the ground/track. And you, on the train, are riding a motorcycle at 100 mph East with respect to the train. (Pretend it's a long flat bed train.) Then your speed with respect to the ground will be 200 mph.

    Is that what you mean?
  6. Feb 14, 2016 #5
    Yes thanks :-)
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