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!

Force Applications

  1. Feb 8, 2006 #1
    Can anyone help me to solve for the distance here ?? i'm lost ...

    A baseball player slides with an initial speed of 7.9 m/s. If the coefficient of kinetic friction between the player and the ground is 0.41, how far does thet player have to slide before comming to rest ?
  2. jcsd
  3. Feb 8, 2006 #2


    User Avatar
    Science Advisor
    Gold Member

    Can you calculate the magnitude of the deceleration (Hint: make a free body diagram and use Newton's second law; the mass of the player will cancel out)?

    (You can also use the work-energy theorem if you have covered that in class.)
  4. Feb 8, 2006 #3

    can anyone expand on this explanation ? im still lost
  5. Feb 8, 2006 #4
    u could calculate force that will decelerate the baseball player using the coefficient of kinetic friciton

    [tex] \mu_k = \frac{F_{fr}}{F_{N}} [/tex]

    figure out the deceleration from that force...

    then use a kinematic equation to solve for distance

    [tex]{v_0^2} = {v_1^2} + 2ax[/tex]
    Last edited: Feb 8, 2006
  6. Feb 9, 2006 #5


    User Avatar
    Science Advisor
    Gold Member

    The only force acting on the player is friction, so Newton's second law gives:

    [tex]F_{net} = ma = f = -\mu mg [/tex]

    The mass cancels out when you solve for a:

    [tex] a = -\mu g [/tex]

    Now that you have the magnitude of the acceleration, you can use the kinematic equation suggested by teken894, which should be written:

    [tex] v^2 = v_o^2 + 2a\Delta x [/tex]
    Last edited: Feb 9, 2006
  7. Feb 9, 2006 #6


    User Avatar
    Homework Helper

    Nope, it shouldn't be written like that. It should instead read:
    [tex]v ^ 2 = v_0 ^ 2 + 2ad[/tex]
    Note that it's v2 not v. :)
  8. Feb 9, 2006 #7


    User Avatar
    Science Advisor
    Gold Member

    Oops. Sorry about the typo. Fixed now.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Force Applications