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Homework Help: Speed and distance problem

  1. Sep 30, 2009 #1
    1. The problem statement, all variables and given/known data

    If a salmon swims straight upward in the water fast enough to break through the surface at a speed of 5m/s, how high can it jump above the water?

    2. Relevant equations
    I am not sure which equation to use.

    3. The attempt at a solution

    0 + 5/2 = 2.5m ??

    Is this correct? If not, which equation do I have to use?
  2. jcsd
  3. Sep 30, 2009 #2
    I would use the energy principle. When it breaks through the water it has only kinetic energy E=1/2*mv2. At it's highest point it has only potential energy E=mgh (where h is the height, I'm not really sure if h is used worldwide or if it's just here in Finland). This gives you an equation system.
  4. Sep 30, 2009 #3


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    Science Advisor
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    Welcome to PF!

    Hi mkerikss! Welcome to PF! :smile:

    Yes, I think h is height everywhere that has an h. :biggrin:
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