1. Limited time only! Sign up for a free 30min personal 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 forces playing the role of centripetal force

  1. Aug 30, 2011 #1
    Can you describe( graphically,like a diagram,or a picture) how a friction force plays the role of the centripetal force?For example, a car performing an uniform circular motion on a plane in a idela situation.The car will perform the turn because of friction forces between tyres and surface.But I can't visualize it so clearly as a situation which consists of a wire attached to a rigid body which makes it spin around an axis,assuming the tension exerted on the cable the role of centripetal force.In the case of friction on steering tyres,I accept friction force having the same direction as the centripetal force because the radial acceleration has the same direction and sense as the latter(as m numeric value in F=ma is always positive ).So,can you help me would a free body diagram would be drawn?
  2. jcsd
  3. Aug 30, 2011 #2


    User Avatar
    Homework Helper

    The angle beween the direction of the front tires and the rear tires and the distance from front to rear tires determines the geometrical circular path the car would take if there is no load. The car follows the circular path because the tires roll in that direction and are not sliding across the pavement. Due to a twisting like deformation of the contact patch of the tires, the actual path radius will be slightly larger than the geometrical radius, depending on how far "outwards" the contact patch is twisted, which is related to the side load and stiffness of the tires.

    The cornering load (centripetal acceleration times mass of car) results in an equal and opposing pair of forces at the tire contact patches; the tires exert an outwards force onto the pavement, coexistant with the pavement exerting an inwards force on the tires.
  4. Aug 31, 2011 #3
    Yeah,that really makes sense.The solution was not so simple as I expected it to be,but I got it now.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook