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Homework Help: Work and velocity question

  1. Nov 20, 2008 #1
    The only force acting on a 1.8 kg body as it moves along the positive x axis has an x component Fx = - 6x N, where x is in meters. The velocity of the body at x = 3.0 m is 8.0 m/s.

    (a) What is the velocity of the body at x = 4.0 m?

    (b) At what positive value of x will the body have a velocity of 5.0 m/s?

    I think to start off i need to take the integral of Fx=-6xN, which would be -3x^2. But from there i'm a bit confused. It doesn't give the force acting on it, so i don't know how to find the work since W=F*Fx.
  2. jcsd
  3. Nov 20, 2008 #2
    The integral you did IS the work.
    You did integral of Fx*dx and this is dW . The integral is the total work.

    And no, the work is not W=F*Fx.
    Fx is the force
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