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Homework Help: Nonconservative work while swimming

  1. Nov 4, 2008 #1
    1. The problem statement, all variables and given/known data


    Starting at rest at the edge of a swimming pool, a 67.0 athlete swims along the surface of the water and reaches a speed of 1.15 by doing the work = 171 . Find the nonconservative work, , done by the water on the athlete.

    2. Relevant equations

    (m)(a)(x initial) + .5 (m)(v^2 initial) = (m)(a)(x final) + .5 (m)(v^2 final)
    E=UK
    W=Fd
    F=ma
    K=.5 mv^2
    3. The attempt at a solution

    Im not really sure how to tackle this problem those are the equations i think i need to use but should it go something like

    K=.5(67kg)(1.15m/s^2) so K=44.3
    E=UK (U being the work?) E= (171)(44.3) E=7575.3

    i dont know what im doin i need some help that'd be great
     
    Last edited: Nov 4, 2008
  2. jcsd
  3. Nov 4, 2008 #2
     
  4. Nov 4, 2008 #3
    sorry i wrote that down wrong but your saying i want to use W=Delta Ek ? how do i go about that tho? by using K=.5 mv^2?
     
  5. Nov 4, 2008 #4
    Think again about the physics... NOT just equations!
    You're swimming. You use some chemical energy to do that: how much?

    Then: what do you get out of it?

    Then: As the problem asks for: Did you get everything out of it that you could have if the situation worked perfect for you? If not: what did you lose in the process?
     
  6. Nov 4, 2008 #5
    yes so while swimming my conservative energy would be 77.05 and in a nonconservative force im losing some of that energy due to the friction and the heat that im giving off etc. to solve for this equation do i need to find the distance i have swam ? i understand why it happend just now how to calculate the lose
     
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