1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Friction as centripetal force...problem with the mass

  1. May 29, 2015 #1
    1. The problem statement, all variables and given/known data

    The problem is that if I have a 5kg mass and 1 kg mass at the same radius with the same μ....and I increase slowly the angular speed ω....then the first mass that will stop the circular motion is the one of the 5 kg mass because needs more centripetal force.Can someone say that this is not true and the two objects will stop at the same time the circular motion because ofthe equations T=m(u^2)/r μΝ=m(u^2)/r μ(mg)=m(u^2)/r. μg=(u^2)/r. ??????
    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. May 29, 2015 #2
    I have big problem......because if you see the equation μg=u^2/r you can assume that the two objects will leave at the same time.....
     
  4. May 29, 2015 #3
    This is not true.
     
  5. May 29, 2015 #4
    Yes if you see the equation F=mω^2R......then you will come to the conclusion that the one with the bigger mass will stop first to moving circular because need more centripetal force..............Yes but also at the bigger mass I have bigger friction....T=μΝ. Τ=μ(mg)....so why two masses are not stopping the circular motion at the same time???????
     
  6. May 29, 2015 #5
    They should stop at the same time.
     
  7. May 29, 2015 #6
    No...if you do the experiment the bigger mass stop first the circular motion
     
  8. May 29, 2015 #7

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    This problem is not well defined. You haven't given enough details.

    From the sparse description, I don't see how centripetal force is involved at all.
     
  9. May 29, 2015 #8
  10. May 29, 2015 #9
    But m1 has also bigger friction......because of the bigger mass...so they must leave at the same time
     
  11. May 29, 2015 #10

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    Please describe the experiment in detail. Are they both resting on a flat rotating surface, perhaps? What are the shapes and widths of the objects, and how far are their mass centres from the axis?
     
  12. May 30, 2015 #11
    Haruspex you are GENIUS.....OF course if it is a float rotating surface...they will stop rotation at the same time....,but if it's not.....and the maximum Ts is the same then...the bigger mass will stop rotation first
     
  13. May 30, 2015 #12

    SammyS

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper
    Gold Member

    Please describe the experiment in detail.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Friction as centripetal force...problem with the mass
Loading...