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Mechanics Newton's 2nd law question

  1. Nov 14, 2009 #1
    1. The problem statement, all variables and given/known data
    A load of 200kg is lifted through 50m by a vertical cable. The load accelerates uniformly from rest for 20 seconds, travels at constant speed for 10 seconds then decelerates to rest in a further 10 seconds. Find the maximum speed attained and the tension in the cable at each stage.



    2. Relevant equations
    F=ma and maybe some SUVAT ones?



    3. The attempt at a solution
    I started using F=ma so that for the first stage I got T=200a+1960 but soon after that I got a bit confused.

    Help would be really appreciated because I'm stuck!
    Thanks!
     
  2. jcsd
  3. Nov 14, 2009 #2

    tiny-tim

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    Science Advisor
    Homework Helper

    Hi pianogirl! :smile:

    Forget the tension … you need to find the acceleration before you can find the tension. :wink:

    Write out the standard constant acceleration equations for the three stages of motion, plus the equation that says the three distances add to 50m.

    What do you get? :smile:
     
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