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!

Question about falling bodies

  1. May 1, 2010 #1
    What force(s) are at work when a spherical object, rolling down an angled surface, tends to adhere to the surface, if only for a short while? Does such a thing exist or am I playing fast and loose with the laws of nature?

  2. jcsd
  3. May 1, 2010 #2
    What do you mean by adhere? Are you saying the sphere is sticky and sticks to the surface?
  4. May 1, 2010 #3
    Thanks for replying.

    No, not sticky in the standard sense of the word. I was hoping there might be physical forces at work while the sphere was rolling that would make it less likely to depart from the surface -- if only for a few seconds.

    This is for a work of fiction, so I'm less interested in exactitude as I am in giving the scene an authentic feeling.
  5. May 1, 2010 #4
    If the surface is less than vertical, the ball will roll down it, otherwise, it will fall.
  6. May 1, 2010 #5
    I realize that. The surface is only *slightly* less than vertical. What I'm asking is, what specific forces are at work?
  7. May 1, 2010 #6
    theres the gravity force and there is the force of friction at the point of contact between the sphere and the surface.
  8. May 2, 2010 #7
    When a ball sits on the surface, it might linger there for a moment because it takes time to accelerate after it's released. There might be some force of adhesion between the ball and the surface. Adhesion depends on the material structure and composition of the ball, surface, and the environmental parameters like temperature. There will also be some resistance from the air around the ball, which has to be displaced in order for the ball to move through it. I can't think of any other major forces involved, in a simple scenario.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook