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Conservation of energy game

  1. Aug 2, 2011 #1
    1. The problem statement, all variables and given/known data
    Conservation of energy
    You are designing a game for small children and want to see if the
    ball’s maximum speed is sufficient to require the use of goggles. In your game, a
    15.0-g ball is to be shot from a spring gun whose spring has a force constant of
    600 N/m. The spring will be compressed 5.00 cm when in use. How fast will the
    ball be moving as it leaves the gun and how high will the ball go if the gun is
    aimed vertically upward? What would be your recommendation on the use of

    I have set the gravitational potential energy zero at the mouth of the gun; therefore, the initial gravitational potential energy is negative.

    Could anyone help?
    Thank you.

    2. Relevant equations

    3. The attempt at a solution
    My velocity's answer is different than the one from the book.

    Wext = ΔK + ΔU g + ΔU s = 0
    or, because Ki = Us,f = Ug,f = 0, **"f" as in final**

    (1/2)m(vf)^(2) - mgx − (1/2)k (x)^(2) = 0
  2. jcsd
  3. Aug 2, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    OK, but what's the change in gravitational PE?
  4. Aug 2, 2011 #3
    -+-= +.

    Thank you.
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