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Homework Help: Help with 2 simple highschool physics Problem

  1. Jan 20, 2008 #1
    :redface: I am really tired and i cant sem to thik right. Please help with these 2 questions




    1. The problem statement, all variables and given/known data

    1. If you must average 60 km/h for a 90-km trip, and only average 40 km/h for the first 40 km, wha velocity must you average the rest of the way?

    2. Juanita left on a walk 45 min ago. She is travelling a 4.5km/h. How fast must you travel to catch up to her in 1.0 h?


    2. Relevant equations

    v: d/t


    3. The attempt at a solution

    ??
     
  2. jcsd
  3. Jan 20, 2008 #2

    dlgoff

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    Science Advisor
    Gold Member

    1. How much time would it take if you were going 90km at 60km/h?
    How much time have you spent going 40km/h?
    So how fast will you have to go for the next 50km in the time you have left?
     
  4. Jan 20, 2008 #3
    #2

    As for #2, how much has Juanita traveled in 45 minutes?
    How much will she have traveled once you have caught up to her? (in 1 hour and 45 mins)

    that should help
    qk
     
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