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Homework Help: Inclined plane car out of gas problem

  1. Sep 18, 2006 #1
    A car traveling at 25.0m/s runs out of gas while traveling up a 22.0 degree slope.
    How far up the hill will it coast before starting to roll back down?

    i tried doing (2*25m/s)^2 / cos22*-9.8cos68 but that wasn't the right answer...

    ~help please?
     
    Last edited: Sep 18, 2006
  2. jcsd
  3. Sep 18, 2006 #2
    what equation are you using? have you drawn a force diagram?
     
  4. Sep 18, 2006 #3

    Hootenanny

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    Alternatively, one could consider the work-energy theorem
     
  5. Sep 18, 2006 #4
    When i comes to inclined slope like these part of the g is "filtered" off. Thus Draw out your free body diagram, resolve the g in the direction parrallel to the slope.


    then use the formular V^2 = U^2 + 2as



    Hope it helps.

    EDITED version
    sry ><
     
    Last edited: Sep 18, 2006
  6. Sep 18, 2006 #5

    Hootenanny

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    Delzac, please do not post complete solutions.

    Edit: No problems Delzac
     
    Last edited: Sep 18, 2006
  7. Sep 18, 2006 #6
    most defiantly, that's how i first looked at it. from the looks of it though they haven't started studying energy yet (at least that's what i think) and i was ify on possible jumping ahead.
     
  8. Sep 18, 2006 #7
    well, now that the correct formula has been given, does the car accelerate? if so, how would you find the acceleration rate of the car?
     
  9. Sep 18, 2006 #8
    how can you be sure that the acceleration or retardation here is constant?
     
  10. Sep 18, 2006 #9

    Hootenanny

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    Is the acceleration due to gravity (approximately) constant here?
     
  11. Oct 25, 2008 #10
    I got 85m by solving for a then using v^2=v1^2+2ad
     
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