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Lifting a crate magnitude of forces.

  1. Oct 10, 2011 #1
    1. The problem statement, all variables and given/known data

    a woman is straining to lift a large crate with no sucess. its too heavy. we denote the forces on the crate as follows: P is the upward force on the crate by the person. C is the contact force on the crate by the floor and w is the weight. how are the magnitudes related while the person is unsucessfully trying to lift the crate.
    P+C>W
    P=C
    P+C=W

    2. Relevant equations

    none??

    3. The attempt at a solution
    im guessing its not the second one because weight isnt even in that equation
     
    Last edited: Oct 10, 2011
  2. jcsd
  3. Oct 10, 2011 #2

    SammyS

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    The problem statement appears to be garbled.

    What is the problem supposed to say???
     
  4. Oct 10, 2011 #3
    i fixed it.
     
  5. Oct 10, 2011 #4

    SammyS

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    I'm guessing that to be successful in your physics course you will need to do more than guess.

    Why or why not: P+C>W ?

    Why or why not: P=C ?

    Why or why not: P+C=W ?
     
  6. Oct 10, 2011 #5
    haha. well not the first one because the force of the woman pulling up plus the floor pushing up cant be greater than the weight or she could lift it.
    not the second one because the forces go in the same direction
     
  7. Oct 10, 2011 #6

    SammyS

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    Actually it could be that P = C.

    Why or why not: P+C=W ?
     
  8. Oct 10, 2011 #7
    um i guess if P+C=W the crate would be still. Because the forces equal the weight? so it could be this one
     
  9. Oct 10, 2011 #8

    SammyS

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    It could be this one, but likely it's like the first one, but with the > flipped to < .
     
  10. Oct 10, 2011 #9
    its not. thats what i had the first time and it was wrong. You cant flip it.
     
  11. Oct 10, 2011 #10

    SammyS

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    I can. Probably you can't.
     
  12. Oct 10, 2011 #11
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