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Homework Help: Speedboat Acceleration Question

  1. Oct 23, 2008 #1
    1. The problem statement, all variables and given/known data
    A speedboat moving at 31.0 m/s approaches a no-wake buoy marker 100 m ahead. The pilot slows the boat with a constant acceleration of -3.5 m/s2 by reducing the throttle.
    (a) How long does it take the boat to reach the buoy?
    ______ s
    (b) What is the velocity of the boat when it reaches the buoy?
    ______ m/s


    2. Relevant equations
    a = (vf-vi)/t
    vf = vi + at
    d = vit + (1/2)at^2
    vf^2 = vi^2 + 2ad


    3. The attempt at a solution

    I keep getting an incorrect answer, but this is what I have been doing.
    100 = 31t + (1/2)(-3.5)t^2
     
  2. jcsd
  3. Oct 23, 2008 #2
    Nevermind I got it! How do you delete threads. I feel really bad leaving this up here when I figured it out myself, but I don't know how to delete!!
     
  4. Oct 23, 2008 #3

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi aquapod17! :smile:

    You can't delete, you can only do a "never mind" post :biggrin:

    but it's ok … lots of members do that …

    I think having to type it out for PF actually helps to make the question clearer! :smile:
     
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