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Homework Help: Friction and Banked road question

  1. Oct 31, 2008 #1
    Hello Everybody. I am having a very difficult time with these two questions.

    The first question:

    The system shown in Figure 4.54 has an acceleration of magnitude 1.77 m/s2, where m1 = 3.90 kg and m2 = 9.40 kg. Assume that the coefficient of kinetic friction between block and incline is the same for both inclines.


    Figure 4.54
    http://www.webassign.net/serpop/p4-54alt.gif

    a)Find the coefficient of kinetic friction.?

    b)Find the tension in the string. (N)

    The Second Question:

    A car rounds a banked curve as in the figure below. The radius of curvature of the road is R, the banking angle is θ, and the coefficient of static friction is μs.

    http://www.webassign.net/serpop/5-13.gif

    a)Determine the range of speeds the car can have without slipping up or down the banked surface. (Use theta for θ, mu for μs, R and g as necessary.)

    vmin =

    vmax=



    b)Find the minimum value for μs such that the minimum speed is zero. (Use theta for θ, and R and g as necessary.)

    μs =


    c)What is the range of speeds possible if R = 100 m, θ = 10.0°, and μs = 0.110 (slippery conditions)?

    vmin =


    vmax=

    -----------------------------

    I would really appreciate it if someone could help me.
    Thanks in Advance....
     
  2. jcsd
  3. Nov 1, 2008 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi msq126! Welcome to PF! :smile:

    Hint: try good ol' Newton's second law for both questions. :wink:

    Anyway, show us what you've tried, and where you're stuck, and then we'll know how to help. :smile:
     
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