Results 1 to 5 of 5

Math Help - Friction problem

  1. #1
    Junior Member
    Joined
    Oct 2012
    From
    UK
    Posts
    34

    Friction problem

    A shopper picks up a 2kg packet of pasta with the thumb and index finger of one hand. The coef of friction between his fingers and the wrapping is 0.3. What horizontal force must he exert to prevent the packet from slipping?

    2sin30*0.3 ( angle betweenfingers and wrapping) not sure help me out
    Follow Math Help Forum on Facebook and Google+

  2. #2
    fkf
    fkf is offline
    Junior Member fkf's Avatar
    Joined
    Nov 2012
    From
    Sweden
    Posts
    70
    Thanks
    9

    Re: Friction problem

    Quote Originally Posted by mysur View Post
    A shopper picks up a 2kg packet of pasta with the thumb and index finger of one hand. The coef of friction between his fingers and the wrapping is 0.3. What horizontal force must he exert to prevent the packet from slipping?

    2sin30*0.3 ( angle betweenfingers and wrapping) not sure help me out
    The gravity pulls on the packet with a force equal to

    F = mg => F = 2*10 = 20 N

    The friction needs to be as large as the gravitational force, so that the packet won't move anywhere. The force by the friction is proportional to the normal force by the factor of coef of friction. That we have

    F = μN <=> N = F/μ => N = 20/0.3 ≈ 67 N or with correct significant figures 0.07 kN.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Oct 2012
    From
    UK
    Posts
    34

    Re: Friction problem

    Thank you very mcuh for the detail explanation and your time.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Oct 2012
    From
    UK
    Posts
    34

    Re: Friction problem

    But the answer given is 32.7N , p,ease help me out
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Nov 2012
    From
    Abu Dhabi
    Posts
    55
    Thanks
    3

    Re: Friction problem

    You have 2 normal contact forces so the frictional force will be directly proportional to 2N

    F=0.3(2N) => N= 20/0.6 => N= 33.3 Nff.bmp
    Last edited by puresoul; December 3rd 2012 at 01:32 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Problem involving Tension and Friction on a slope
    Posted in the Advanced Applied Math Forum
    Replies: 0
    Last Post: February 24th 2010, 12:55 AM
  2. static friction problem
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: October 15th 2007, 01:31 PM
  3. Friction problem help
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: July 26th 2007, 07:06 AM
  4. physics-static friction + kinetic friction between blocks
    Posted in the Advanced Applied Math Forum
    Replies: 3
    Last Post: February 20th 2007, 06:14 AM
  5. Friction and coefficient of friction questions!
    Posted in the Advanced Math Topics Forum
    Replies: 1
    Last Post: March 17th 2006, 09:45 PM

Search Tags


/mathhelpforum @mathhelpforum