1. PF Insights is off to a great start! Fresh and interesting articles on all things science and math. Here: PF Insights

Find work done given time, acceleration, and mass

  1. a box with a mass of 6.0 kg is accelerated from rest by a force across a floor at a rate of
    2.2 m/s^2 for 5.9 s. Find the net work done on the box

    m=6.0kg
    a=2.2m/s^2
    t=5.9 s
    a=0 degrees

    i know W=Fdcos(a)
    and F=ma


    so,
    F=6.0kg*2.2m/s^2=13.2N
    W=13.2N*d*cos0=13.2N*d

    I am a little unsure as how to find d though. would it be one of the kinematic equations?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. tiny-tim

    tiny-tim 26,054
    Science Advisor
    Homework Helper

    hi daltomagne! :smile:

    (try using the X2 icon just above the Reply box :wink:)
    That's right. :smile:

    You can either use one of the standard constant acceleration equations to find d, or you can use another of them to find vf, and then apply the work-energy theorem ( work done = change in mechanical energy).
     
  4. so i'm thinking v=vi+at and that gives me vi=-12.98m/s
    and
    xf=xi+vit+1/2at2?
    but that gives me a value for x=-38.3 m?

    so something isn't adding up
     
  5. tiny-tim

    tiny-tim 26,054
    Science Advisor
    Homework Helper

    where's the contradiction? :confused:

    one figure is speed, the other is distance, they should both give you the same work. :wink:
     
Know someone interested in this topic? Share a link to this question via email, Google+, Twitter, or Facebook

Have something to add?