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TBR CBT 1 #24 on Friction

Discussion in 'MCAT Study Question Q&A' started by Whiteshoes, Jul 23, 2011.

  1. Whiteshoes

    Whiteshoes Member
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    Taking into account that a car slows during the reaction distance and the breaking distance, what happens when the kinetic coefficient of friction for the road (μk) is increased?

    side note: The reaction distance is defined as the distance the vehicle travels before the driver reacts to the braking trigger.

    My thought: I understand why braking distance will decrease because while you are braking you are skidding. Skidding depends on μk However that should not affect the reaction distance because during reaction distance you are still under static friction.

    My choice: The braking distance will decrease, while the reaction distance will be unchanged.

    CORRECT ANSWER:

    Both the braking distance and the reaction distance will decrease.


    Can anyone help me? thanks
     
  2. zwander

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    Sounds pretty ridiculous, but the passage says the car slows before braking aka friction is acting on the car during the reaction distance. So even before you slam on the brakes and cause that super huge -a, that car slows down faster before the brakes causing a shorter distance for both.
     

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