1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Ball moving up an incline and coming down.

  1. Nov 27, 2006 #1
    "a ball is rolled up an incline (at an angle x with the horizontal). For the angle x and the ball involved, the acceleration of the ball is 0.25g and directed down the incline. If the ball is released with speed v, determine the distance it moved up the incline before reversing its direction as a term of all other variables. What is the minimum initial velocity?"

    Anyone can give me a hint on how to approach this problem? :(
    Last edited: Nov 27, 2006
  2. jcsd
  3. Nov 27, 2006 #2


    User Avatar
    Homework Helper

    Well, try to present us some of your work, there must be some thoughts on how to solve the problem.
  4. Nov 27, 2006 #3
    This is what I have so far..

    Using equation of motion..

    Vf^2 = Vi^2 + 2*a*x

    a = 0.25g = 0.25*(-9.8 m/s^2) = -2.45 m/s^2

    Vf = 0 m/s
    Vi = ?
    x = s = ?

    0 = Vi^2 + 2(-2.45 m/s^2)x
    0 = Vi^2 - 4.9 m/s^2 * x

    -Vi^2 = -4.9 m/s^2 * x

    Vi^2 = 4.9 m/s^2 *x

    x = vi^2/4.9 m/s^2
  5. Nov 27, 2006 #4
    Gave up? :(
  6. Nov 27, 2006 #5


    User Avatar
    Homework Helper

    No need to give up, since the answer seems correct. :smile:
  7. Nov 27, 2006 #6
    For this problem based on the given information that th acceleration is 0.25g down the incline plane, can I assume then that the angle is...

    0.25g = gsin(theta)
    theta = 14.47 deg ?
  8. Nov 27, 2006 #7


    User Avatar
    Homework Helper

    You have nothing to assume, since the accelearion is 0.25g, which must equal g sin(theta), so theta ≈ 14.47 deg.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook