1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Uniform circular motion (I DON'T KNOW)

  1. Oct 31, 2005 #1
    WHAT IS THE MAXIMUM SPEED WITH WHICH A 1050KG CAR CAN ROUND A TURN OF RADIUS 77M ON A FLAT ROAD IF THE COESFFIECENT OF STATIC FRICTION BETWEEN TIRES AND ROAD IS .80? here is what I have so far?

    m= 1050kg
    r =77m
    uk =.080
    FN=mg FR =ukfn
    (1050kg)(9.8m/s) = FN = 10290N
    (.80) (10290) = 8232N= FR
    A= F/m a=10290N + 8232N/1050 17.64M/S^2
    SPEED = X/T 77/17.64 =4.4m/s
    Not sure am I right?
     
  2. jcsd
  3. Oct 31, 2005 #2
    At max speed:
    F_s = ma
    F_s = u_s * N = u_s*mg

    Remember that a = v^2/r and solve for v.
     
  4. Oct 31, 2005 #3
    reply

    v= squre root of (9.8m/s^2)(77m) = is the maxium speed 27.46m/s
     
    Last edited: Oct 31, 2005
  5. Oct 31, 2005 #4
    You don't need to know time.

    F_s = ma

    You know F_s, you know m and you know that a = v^2/r
     
  6. Oct 31, 2005 #5

    ranger

    User Avatar
    Gold Member

    [
    Why did you use acceleration = 9.80 m/s/s ?
    The car is on a flat surface with acceleration directed along the x-axis. This causes the car to move forward. Force of gravity acts on the y-axis pulling an object downward.

    [​IMG]


    http://www.physicsclassroom.com/Class/circles/U6L2a.html
     
    Last edited: Oct 31, 2005
  7. Oct 31, 2005 #6
    is F_S IS TOTAL Force
     
  8. Oct 31, 2005 #7

    ranger

    User Avatar
    Gold Member

    Fnet is simply the sum of all the forces.

    Please read this. I'm sure that will help you. Pay special attention to those examples.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?