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Homework Help: Change of speed of a car turning in circles

  1. Jan 5, 2014 #1
    My textbook says : "The friction force on a car turning a corner does no work."

    I agree somewhat. However, if there is no work, there is no change of speed, aka no change of kinetic energy.

    How can a car in a real-life stop if it is doing perfect circles with forces pointing towards the center of those circles?

    Is there another component of friction in play?
  2. jcsd
  3. Jan 5, 2014 #2
    I forgot to mention: I imply that the car driver is neither pushing the gas pedal nor the brakes!
  4. Jan 5, 2014 #3
    Yes...There has to be a component of friction in tangential direction providing the required deceleration (i.e causing the speed to reduce ) .
  5. Jan 5, 2014 #4


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    The car does not stop when turning a corner - it moves along a circle.

    Its velocity changes direction, but not magnitude. The speed stay constant.

    When a car stops, some force is applied parallel to its velocity, opposite to it.

  6. Jan 5, 2014 #5


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    Tania beating me again:biggrin:

  7. Jan 5, 2014 #6
    I saw you typing but didn’t notice you were replying to this thread :wink:
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