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Homework Help: How far does the train travel before the engine is ...

  1. Oct 4, 2015 #1
    1. The problem statement, all variables and given/known data.
    A model steam train engine has a mass of 2.3 kg is powered by a sterno and white gas mixture that heats a small boiler. Once sufficient steam pressure is produced, the train is released from rest. The train travels along a straight and level track. At any time after release and before it comes to rest, the train’s speed can be expressed by v = 5t + 2t 2 − t 3 .

    a) How far does the train travel before the engine is producing maximum force?

    2. Relevant equations

    3. The attempt at a solution
    I've only been thinking on how i can approach this problem and I haven't had any luck. I've tried drawing Free body Diagrams and drawing forces but it's not helping and its because i dont really understand what they are asking for.

    Am I looking for a displacement? Now i know the initial position is 0 since it was released from rest.
    Now I am guessing max force is the force needed to get the train moving?
    Please help.
  2. jcsd
  3. Oct 4, 2015 #2
    The v= 5t+2t^2-t^3
  4. Oct 4, 2015 #3

    Mister T

    User Avatar
    Science Advisor
    Gold Member

    Released from rest means the initial velocity is zero.

    When the force has its maximum value, what can you say about the acceleration?
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