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Homework Help: Conservation of Enery (roller coaster)

  1. Nov 4, 2007 #1
    ok i this question has been asked but whoever asked it did not show work therefore did not have it answered so here we go my attempt!!

    1. The problem statement, all variables and given/known data

    Show that on a roller coaster with a circular vertical loop the difference in your apparent weight at the top of the loop and the bottom of the loop is 6 g's that is 6 times your weight. ignore friction.

    h = height of start of roller coaster
    R = loop's radius

    2. Relevant equations

    PE = KE
    a = v^2/R

    3. The attempt at a solution

    at the top of loop: mgh = mg2R + .5mv^2
    solved for velocity v^2 = 2g(h-2R)
    centripital acceleration is a = v^2/R ---> a = 2g(h-2R)/R

    also i knew from another problem that minimum h had to be 2.5R to be able to go through the whole loop and stay on track so...

    a = g? haha yeah i am lost i have no idea what to do. I am trying to teach this course to myself and i am really struggling without a teacher. Please help?
  2. jcsd
  3. Nov 4, 2007 #2


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    Science Advisor
    Homework Helper

    Are you sure you have the problem stated correctly? It's pretty easy to show the sum of the apparent weights at the top and bottom is 6mg.
  4. Nov 6, 2007 #3
    yes problem is state correctly and do tell how maybe im just over thinking it.
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