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Homework Help: Velocity/displacement problem

  1. Aug 17, 2015 #1
    1. The problem statement, all variables and given/known data
    For each function, find an expression for the velocity and the value of the displacement and velocity at t=5. Displacement is in metres and time is in seconds.

    2. Relevant equations
    s(t) = 3t + 7

    B) s(t) = t3 - 2t2 + 4t - 1

    3. The attempt at a solution

    s(t) = 3t + 7
    s(5) = 3(5) + 7
    = 22 m/s

    B) s(t) = t3 - 2t2 + 4t - 1
    s(5) = 53 - 2(5) + 4(5) - 1
    =94 m/s

  2. jcsd
  3. Aug 17, 2015 #2


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    Staff Emeritus
    Science Advisor
    Homework Helper

    s usually denotes position or displacement, not velocity. How do you find velocity from displacement?

    Remember, the problem is asking you to find both displacement and velocity at a given time, t.

    Hint: You posted this problem in the Calculus HW forum, yet you used no calculus. Didn't you find that a little odd?
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