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Homework Help: Another kinematics question

  1. Nov 23, 2007 #1
    1. The problem statement, all variables and given/known data
    A train accelirates uniformly from rest to reach a speed of 54km/hr in 200 seconds after which the speed remains constant for 300 seconds, At the end of this time the train decelerates to rest in 150 seconds.

    Calculate the acceleration and retardation.

    2. Relevant equations
    s= ut
    v= u+at
    s=ut + 0.5*at^2

    3. The attempt at a solution

    a = (v-u)/t = 54/(200/60*60)=972km/h^2

    is the first part correct? i'm not really sure what to do next.
  2. jcsd
  3. Nov 23, 2007 #2
    First part is correct; in second part speed is constant, hence no acceleration and third part is similar to first part.
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