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Homework Help: Acceleration of a car?

  1. Sep 29, 2010 #1
    1. The problem statement, all variables and given/known data
    A car is moving at 50.0 m/s and brakes to a halt in 6.00 seconds.
    (1)From the time it starts braking, how far does the car travel before the car comes to a halt if its acceleration is constant?
    (2)What is the car's speed 1.35 s after it starts to brake if the cars acceleration is constant?


    2. Relevant equations
    v=a*t+vo


    3. The attempt at a solution
    I really just don't where to start with this problem. I'm confused! Please help!
     
  2. jcsd
  3. Sep 29, 2010 #2

    fss

    User Avatar

    The equation you listed will get you the acceleration, but for the distance you'll need

    [tex]v_f^2 = v_0^2 + 2ad[/tex]
     
  4. Sep 29, 2010 #3
    Ok thank you! I was able to find the distance for question one but I am still stuck as to what is the car's speed 1.35 s after it starts to brake if the cars acceleration is constant?
     
  5. Sep 29, 2010 #4

    fss

    User Avatar

    Just use the first formula you gave in your original post. Pay attention to your signs and you'll be golden.
     
  6. Sep 29, 2010 #5
    Got it. Thanks!
     
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