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Homework Help: Velocity/Acceleration/displacement Help

  1. Oct 21, 2008 #1
    1. The problem statement, all variables and given/known data

    I need help with acceleration/displacment, mainly how far something moves during a acceleratopn period

    2. Relevant equations

    Alright, right now i am learning about velocity and acceletarion and i have a question/problem i need help with.

    I know the formula for acceleration and stuff, but how do you find out how far the an object. in this case a car moved during the breaking period?

    This is the exact question:
    A driver of a car traveling at 15 m/s applies the breaks, causing a uniform acceleration of -2.0 m/s^2. how long does it take the car to accelerate to a final speed of 10.0 m/s? How far has the car moved druing the breaking period?

    3. The attempt at a solution
  2. jcsd
  3. Oct 21, 2008 #2


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    Homework Helper

    Here are some equations that might help:

    You know a and V and want to find t. And then you want to find X.
  4. Oct 21, 2008 #3
    Ah I see. then does accelaration even matter?
    Can't you just do Change in velocity Times change in time?
  5. Oct 21, 2008 #4


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    Homework Helper

    Of course acceleration matters. When you don't have the time as in this problem you need the acceleration to determine the unknown time. Now for this question they also ask what the distance is and that can be found from a formula for known velocities and acceleration.
  6. Oct 22, 2008 #5
    yeah thats what i meant, i got the first part i needed help with how far/distance it traveld after it accelerated. but yeah i get it now thanks
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