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!

Newton's Laws Finding Applied Force and other Forces

  1. Mar 29, 2012 #1
    1. Sean the skier is headed for a rough patch of snow with the coeffcient of friction 0.20. Find his acceleration if his mass is 50 kg.



    2. F=ma, coeffcient of friction=Ff/Fn



    3. Fgravity = 490.5 using the equation coeffcient of friction=Ff/Fn we get 0.20 = Ff/490.5 which equals Ff = 98.1
    This is where i get stuck. i do not know how to find the Force applied to use it to find the sum of the two forces (force applied and force of friction) to plug into the equation F= ma.
     
  2. jcsd
  3. Mar 29, 2012 #2
    The sum of forces equals ma (Newtons 2nd law). Use it to write down the equation(s) to be solved.
    You know that the vertical acceleation is zero:
    [itex]0= N - mg\\
    F_{fric} = \mu N=\mu mg\\
    \sum F_{horizontal} = ma = -F_{fric}[/itex]
    So never plug into any equation unless you have a good reason
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook