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Homework Help: Friction, Inclines

  1. Jan 15, 2008 #1
    Hi !

    Can anyone help me ??????????

    Problem :
    1- A coffee cup on the dashboard of a car slides forward on the dash when the driver decelerates from 40 km/h to rest in 3.5 s or less, but not if he decelerates in a longer time. What is the coefficient of static friction between the cup and the dash ?
    2- An 18-kg box is released on a 37*(grade) incline and accelerates down the incline at 0.270 m/s(square). Find the friction force impeding its motion. How large is the coefficient of friction

    Thanks !!!!
    Last edited: Jan 15, 2008
  2. jcsd
  3. Jan 15, 2008 #2

    Tom Mattson

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    According to the rules of this Forum, you must show an attempt at the problem before receiving help.
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