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Homework Help: Initial Acceleration?

  1. May 29, 2010 #1
    Initial Acceleration???

    The force exerted by the wind on a sailboat is approximately perpendicular to the sail and proportional to the component of the wind velocity perpendicular to the sail. For the 950-kg sailboat shown in the figure below, the proportionality constant is

    Water exerts a force along the keel (bottom) of the boat that prevents it from moving sideways, as shown in the figure. Once the boat starts moving forward, water also exerts a drag force backwards on the boat, opposing the forward motion.

    If a 15-knot wind (1 knot = 0.514 m/s) is blowing to the east, what is the initial acceleration (m/s2) of the sailboat?

  2. jcsd
  3. May 30, 2010 #2


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    Welcome to PF!

    Hi DriverX! Welcome to PF! :smile:

    But … is that picture really a sailboat? :confused:

    It looks more like a horse! :biggrin:
  4. May 31, 2010 #3
    Re: Initial Acceleration???

  5. May 31, 2010 #4


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    that's better! :biggrin:

    ok …
    … so find the force exerted by the wind perpendicular to the sail, and so find the forward force, and use F = ma.

    What do you get? :smile:
  6. May 31, 2010 #5
    Re: Initial Acceleration???

    because a force is a vector and the question is in two dimensions, i.e X and Y,
    you can separate the force into it's x and y components

    e.g if you push a block north east (like your sail) at an angle of 45 degrees
    your F vector, is really two forces, one going east in the X direction, and one going north in the Y direction,

    so the Feast = Fcos45 degrees
    and Fnorth = Fsin45 degrees

    you can use this concept (i think? ) to help solve your question
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