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Homework Help: Completely stumped.

  1. Oct 15, 2008 #1
    This is the first time I have encountered a problem like this, and have no idea how to set it up, let alone solve it. Any help would be great.

    1. The problem statement, all variables and given/known data

    A car can decelerate at -5.00 m/s2 without skidding when coming to rest on a level road. What would be the magnitude of its deceleration if the road were inclined at 10° uphill? Assume the same static friction coefficient.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 15, 2008 #2
    It looks like in the first scenario friction is providing the decelerating force while in the second scenario both friction and a component of the force of gravity are slowing the car down.

    You can solve for the coefficient of static friction when the car is simply decelerating on a level rode (mass will cancel out so you do not need to know the car's mass) and use it to solve the net force on the car that is on the incline. (which then can be used to find the acceleration using Newton's second F = ma)
  4. Oct 15, 2008 #3
    I'm still confused, and have no idea what i'm doing.
  5. Oct 16, 2008 #4
    Try drawing a diagram of all the forces acting on the car in both examples. There should only be two - gravity and braking force (friction). Consider the angles the forces act on the car in each example.

    Once you have that, see if MATdaveLACK's post will make more sense.
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