Speed vs Friction

  1. I am just wondering

    In a case, a person can completely pull a mat between a table with and a dining set on top, with the dining set only moving a negligible distance (hence not falling off)

    This can also happen in everyday life, e.g. pulling a paper or any thin sheet between two non-fixed objects.

    The significant technique of the pull involve great speeds.
    Lower speed will move the two or one of the objects significantly.

    On a free fall, an object will reach terminal velocity as it moves at a great speed.
    (greater speed results greater friction.)

    However with the case of the table, mat, and dining set, it appears that greater speed reduces friction.

    Can somebody please explain if there's any link between speed and friction?
    Thank you
  2. jcsd
  3. berkeman

    Staff: Mentor

    I don't think it reduces the coefficients of friction involved. The quick pull just reduces the amount of time that the forces of friction interact with the objects sitting on the tablecloth. Shorter time and same force produces less displacement.
  4. The frictional force is the coefficient of friction(static or kinetic) multiplied by its weight, so it does not change.
    When the pulling involves great speeds, it is just too much for the frictional forces to affect.
    Static friction is more than kinetic friction, so you may see the dining set to move more significantly on the initiation of the pull than later.
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