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Distance traveled using velocity

  1. Feb 16, 2013 #1
    1. A dog runs back and forth between its two owners, who are walking toward one another. The dog starts running when the owners are 10.0m apart. If the dog runs with a speed of 3.0m/s, and the owners each walk with a speed of 1.3m/s , how far has the dog traveled when the owners meet?


    My attempt:
    I know each owner will travel a distance of 5m at 1.3m/s which equals 6.5s of time. The dog travels 3.0m/s for the 6.5s= 19.5m traveled, but the answer given is 11m. What am I doing wrong?
     
  2. jcsd
  3. Feb 16, 2013 #2

    tms

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    How far do you travel in 6.5 sec if you go at 1.3 m/sec?
     
  4. Feb 16, 2013 #3
    Hey physics problems can be tough to get thru sometimes.

    You can use an equation that relates velocity, time, and distance to get your answer.

    Remember, Average velocity = Δx divided by Δt...where x is displacement and t is time. The trick here is also that you have two people moving at the same velocity closing a distance of 10m.

    Once you have the time it takes for these two people to meet, solve for the Δx of the dog.
     
  5. Feb 17, 2013 #4

    NascentOxygen

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    Staff: Mentor

    ....
     
  6. Feb 17, 2013 #5
    You can also simplify the problem by treating one owner as being stationary and the other moving at 2.6m/s

    EDIT: I got 11.5385, which I think you should round up...not quite sure about this method
     
    Last edited: Feb 17, 2013
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