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Homework help, please Urgent

  1. Mar 22, 2007 #1
    Homework help, please!!! Urgent

    This is the question from my physics 11 class, it has completly stumped me, i have done about have the question, i just get stuck when it comes to proving that the persone has or has not caught the bus.

    here it is:

    A personne walking at a speed of 1.7m/s see's a stoped bus 25m from him. At this moment this person starts to run with an acceleration of 1,3m/s2. After 4 secondes this personne has reached his maximum speed et it stays constant, but at the same time the bus starts moving and accelerates 2,6m/s2.

    Does this person suceed in catching the bus? If so, at what time and at what distance, if not what was the smallest distance between the person and the bus.

    - Im sorry if there any mistakes, i translated from french.

    Ive got this so far:

    Alright well, by using the initiale speed of 1,7m/s and 4s, i found his constante speed of 6.9m/s. So after that i used the acceleration and his speed to determine the distance he travelled, 17,2m. i subtracted 17,2m from 25m, which left 7,8m between the bus and the person. Then im stuck, how do i incorporate both speeds in one equations to see if he caught the bus or not?

    Update, i tryed using a time of 8s for both the peron and the bus, and i see that the bus is goin faster then the person and has travelled a dreater distance, the only problem is dont know what has happened between 4s and 8s, im completly lost:confused:
    Last edited: Mar 22, 2007
  2. jcsd
  3. Mar 22, 2007 #2


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    Welcome to PF, Nick. Please note that you must show your work before we can help with homework questions. How far have you got?
  4. Mar 22, 2007 #3


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    Dearly Missed

    To solve such a question:
    1. Write a traversed distance formula for the person and one for the bus, both distance formulas as functions of time.

    Can you do that?
  5. Mar 22, 2007 #4
    i added my work, to the bottom,
  6. Mar 22, 2007 #5
    reply for travers distance formula thing, my classes are in french and i dont know what that means or we didnt learn that yet
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