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What is the coefficient of friction?

  1. Oct 10, 2011 #1
    An object on a 30 degree inclined surface with force applied up the ramp,
    weight of object = 6.9N,
    applied force on object = 3.13N

    My answer was -0.05, but I'm not sure if this is right so I want to make sure with someone's help

    Thanks
     
  2. jcsd
  3. Oct 10, 2011 #2

    SammyS

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    I'm not sure either. Is there a complete question here?

    What's the complete statement of the problem?
     
  4. Oct 10, 2011 #3
    yes the information is complete, I had to take it from a table with info in it so theres no complete statement, and btw theres no acceleration
     
  5. Oct 10, 2011 #4

    SammyS

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    So, these are observed data?

    There's no way to know the coefficient of friction, without more information.

    You can determine the frictional force -- perhaps -- but not the coefficient .
     
  6. Oct 10, 2011 #5
    Ive done it for every other question...but im in grade 11 and our formula for the coefficient of friction is μ=Ff/Fn

    If you don't think theres enough info, could you do just the friction? Thanks
     
  7. Oct 10, 2011 #6

    SammyS

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    That's IF either of the following is true as well as the direction of the applied force is known.

    1. The object is moving at a constant speed. (kinetic friction)

    2. The object is stationary, but just on the verge of moving. (static friction.)
     
  8. Oct 10, 2011 #7
    1. yes
    2. yes

    Im only in gr 11 physics so it wont be very complicated
     
  9. Oct 10, 2011 #8
    The object is on a high friction surface (sand paper) and is just on the verge of moving at a constant velocity
     
  10. Oct 10, 2011 #9
    Negative coefficients of friction do not conserve energy. If you want more help you should post more work.

    edit: forgot to hit "post" and didn't see previous help
     
  11. Oct 10, 2011 #10
    I got negative because since this was a lab, we tried to make the slope 30 degrees but probably wasnt
    Thats why my teach says we may get a negative answer
     
  12. Oct 10, 2011 #11
    So could anyone work out either the coefficient of friction or just friction?
     
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