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Homework Help: Average value help

  1. Apr 13, 2010 #1
    1. The problem statement, all variables and given/known data

    if a freely falling body starts from rest, then its displacement is given by s = (1/2) g(t^2). let the velocity after a time T be vsubt. Show that if we compute the average of the velocities with respect to t we get vsubave = (1/2)vsubt, but if we compute the average of the velocities with respect to s we get vsubave = (2/3)vsubt


    3. The attempt at a solution

    1)okay the first thing that i did was i found the derivate of s = (1/2)gt^2 to find the vsubt which i got vsuvt = gt.

    2) next i vsubt that i found into the average value formula (1/(b-a))integralfora-to-b f(x)dx

    3) then i got (g/(b-a))integralfora-to-b(t)

    4)
     
  2. jcsd
  3. Apr 14, 2010 #2

    HallsofIvy

    User Avatar
    Science Advisor

    You don't need to use an integral. At t= 0, s= 0 and at t, s= (1/2)gt^2 so the total distance moved is (1/2)gt^2. Divide that by t to get the average speed.
     
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