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Homework Help: Find minimum initial velocity of object

  1. Oct 6, 2009 #1
    1. The problem statement, all variables and given/known data
    Find the minimum initial velocity needed for a ball starting from the middle-top (highest point) of a semicircular mound with radius R to go over without touching the mound if the initial velocity has only a horizontal component.

    2. Relevant equations


    3. The attempt at a solution
    this was a question on a test i just had. i didn't have time to prepare to well for this test so i have no idea how i did. i just used the formula v=d/t and substituted the variable R (radius) for d. then i solved fort which equaled t=R/v. then i plugged this value of t into the formula
    "[tex]\Delta[/tex]d=vt+.5at[tex]^{2}[/tex]. with this i just solved for v and i got v=[tex]\sqrt{4.9R}[/tex]. Im pretty sure it is wrong and that i was supposed to use some formula for circular motion or something. could you please help me figure this question out?
  2. jcsd
  3. Oct 6, 2009 #2


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