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Homework Help: KE-1/2mv^2 physics question

  1. Jan 28, 2006 #1
    hi I am new and new to physics i am have alot of trouble with this problem

    mass =1.3kg
    how do i get the velocity

    so far i have it wrote like this

    but dont know how else to do plz help thanks ron
  2. jcsd
  3. Jan 28, 2006 #2
    The equation KE=1/2mv^2 says that the kinetic energy is equal to half of the mass of the object times the object's velocity squared. So you need to solve for velocity (v). Isolate the v variable using algebra (try to get v by itself on one side of the equation).
    Last edited: Jan 28, 2006
  4. Jan 28, 2006 #3
    v=7,98 m/s
  5. Jan 28, 2006 #4


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    You will find that it is easier to do your algebra BEFORE plugging in the numbers. You have

    [tex] \mbox{KE} = \frac 1 2 m v^2 [/tex]
    [tex] 2 \mbox{KE} = m v^2 [/tex]

    [tex] 2 \frac {\mbox{KE}} m = v^2 [/tex]


    [tex] v = \sqrt { 2 \frac {\mbox{KE}} m } [/tex]

    Now you can substitute in your numbers and arrive at the numeric solution.
    Last edited: Jan 28, 2006
  6. Jan 28, 2006 #5
    thank you for the help i have been out of school 24 years and this is my last semester for my degree thanks ron
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