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Two balls, passing in the night

Page history last edited by Joe Redish 5 years, 9 months ago



The figure at the right represents the position vs. clock reading of the motion of two balls, A and B, moving on parallel tracks. Carefully sketch the figure on your homework paper and answer the following questions:


  1. Mark with the symbol ta along the t-axis any instant or instants at which one ball is passing the other.
  2. Which ball is moving faster at clock reading tb?
  1. Mark with the symbol tc along the t-axis any instant or instants at which the balls have the same velocity.
  2. Over the period of time shown in the diagram, which of the following is true of ball B? Explain your answer.
    1. It is speeding up all the time.
    2. It is slowing down all the time.
    3. It is speeding up part of the time and slowing down part of the time.



*From A. Arons, A Guide to Introductory Physics Teaching (John Wiley, 1990).

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