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Homework Help: Impulse and Momentum of an auto

  1. Feb 18, 2015 #1
    1. The problem statement, all variables and given/known data
    An automobile has a mass of 2300 kg and a velocity of
    +16 m/s. It makes a rear-end collision with a stationary car
    whose mass is 1800 kg. The cars lock bumpers and skid off
    together with the wheels locked. (a) What is the velocity of the
    two cars just after the collision? (b) Find the impulse (magnitude
    and direction) that acts on the skidding cars from just after the col-
    lision until they come to a halt. (c) If the coefficient of kinetic fric-
    tion between the wheels of the cars and the pavement is
    0.80, determine how far the cars skid before coming to rest.

    a) v = 9 m/s
    b) FΔt = -36800 Ns

    I need to find only the c part of the problem.

    2. Relevant equations
    The Principle of Conservation of Linear Momentum

    3. The attempt at a solution

    The answer must be s = 5.2 m
  2. jcsd
  3. Feb 18, 2015 #2


    User Avatar
    Education Advisor
    Gold Member

    Where did the formula ug - a = a come from? The coef of friction between the cars and the pavement is 0.8. Both cars. So what acceleration do the cars experience due to friction? Yes, it really is that simple.
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