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Min Power for motor Question

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  1. Dec 10, 2008 #1
    1. The problem statement, all variables and given/known data
    A 1.0X10^3kg elevator carries a maximum load of 800.0 kg. A constant frictional force of 4.0x10^3N retards the elevator's motion upward. What minimum power in kilowatts must the motor deliver to lift the fully loaded elevator at a constant speed of 3.00m/s?


    2. Relevant equations
    This is part of my problem that I don't understand.


    3. The attempt at a solution
    I haven't made an attempt because I do not know the equation. I'm studying for my college finals and this is a question that my friend made for a review. Unfortunately, he is visiting a family member who is expecting to pass soon. Any advice would be great!
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Dec 10, 2008 #2

    Dick

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    Work is force times distance. At constant speed and force, power is force times velocity. That's what you need. What's with the inane poll? The purpose of life is to answer Forum questions from people who don't make an effort.
     
  4. Dec 10, 2008 #3
    i arrived 65.7832 kw.
    Is that correct? man he should have made an answer key.
     
  5. Dec 10, 2008 #4
    is 65.7832 kw the right answer?
     
  6. Dec 10, 2008 #5

    Dick

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    My answer is a little bit different. Not much. What are you using for g?
     
  7. Dec 10, 2008 #6
    9.812 m/s2
     
  8. Dec 10, 2008 #7

    Dick

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    That's the difference. I was using 9.8.
     
  9. Dec 10, 2008 #8
    what did u get?
     
  10. Dec 10, 2008 #9

    Dick

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    64.92kW. The difference is just in the value of g.
     
  11. Dec 10, 2008 #10
    can u check it with 9.812? i dont have a calculator...
     
  12. Dec 10, 2008 #11

    Dick

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    Why? No, I don't want to. Get a calculator. I checked your answer.
     
  13. Dec 10, 2008 #12
    omgravity i dont have one. anywhere. at all. my friend has it. the one in CA right now visiting his family member that could die very soon. i really need your help. it wont take you long at all. please?
     
  14. Dec 10, 2008 #13

    Dick

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    I've consigned you to the 'joke' column. I also hit "report". You'll need another alias. A-hole.
     
  15. Dec 10, 2008 #14
    i reported u too.
     
  16. Dec 11, 2008 #15

    vanesch

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    This silly thread is done.
     
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