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!

Sliding Off A Semi-Circle

  1. Dec 5, 2006 #1
    1. The problem statement, all variables and given/known data
    A boy sits on top of an igloo shaped like a semi-circle of Radius R. He begins to slide down the semi-circle. At what height above the ground does the boy slide off the semi-circle? Assume g=9.8 m/s2, and no friction.
    [​IMG]

    2. Relevant equations
    Conservation of energy? Or centrifugal force?

    3. The attempt at a solution
    Couldn't think of any starting points; tried conservation of energy, but failed. Answer is obviously in terms of R. Can anyone shed the light on this problem?
     
  2. jcsd
  3. Dec 5, 2006 #2

    0rthodontist

    User Avatar
    Science Advisor

    At each point you will need to consider how quickly the boy is moving around the exterior of the circle, and how much force on the boy directed towards the inside of the circle will be needed to keep him moving in a circle at that speed.
     
  4. Dec 5, 2006 #3
    I do not quite understand how I should break gravity into different vectors, or is it even the right approach finding the velocity? The force you are talking about is the centrifugal force right?
    But, my teachers seems to be hinting that conservation of energy is needed. Care to explain further?
     
  5. Dec 5, 2006 #4

    OlderDan

    User Avatar
    Science Advisor
    Homework Helper

    Conservation of energy will tell you the speed of the boy at any height. The speed is related to the centripetal force required to stay in circular motion. Consider all of the forces acting on the boy and resolve them into components in the direction of motion (tangent to the circle until he separates from it) and perpendicular to the motion (the radial direction).
     
  6. Dec 6, 2006 #5

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    To give you a BIG hint:
    WHICH force acting on the boy will be zero when he slides off the semi-circle?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Sliding Off A Semi-Circle
  1. Charged Semi-Circle (Replies: 1)

Loading...