Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need help (physics)

  1. Sep 29, 2005 #1
    got it :) ................
    Last edited: Sep 30, 2005
  2. jcsd
  3. Sep 30, 2005 #2
    I need help please. Anyone majoring in physics please help me out.
    Johnny jumps off a swing, lands sitting down on a grassy 20° slope, and slides 2.5 m down the slope before stopping. The coefficient of kinetic friction between the grass and the seat of Johnny's pants is 0.81, What was his initial speed on the grass?
  4. Sep 30, 2005 #3


    User Avatar
    Science Advisor
    Homework Helper

    His speed down the slope will be

    [tex]v = v_0 + (g \sin 20^o - \mu \cos 20^o) t[/tex]

    (a) Can you figure out where that came from?

    (b) Can you use it to find the distance traveled?

    (c) Can you determine the time at which he traveled 2.5 m?

    (d) Can you guess my next question? ;)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook