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Acceleration Dependent on Velocity

  1. May 1, 2007 #1
    A constant Force F is applied by the engine of a stationary car causing it to move to the right. Opposing force F, is a force of magnitude -kv, where k is a constant and v is the velocity of the car. The car has a mass of m.

    a) Determine the horizontal acceleration in terms of k, v, F and m

    b)Derive the equation expressing the velocity of the car as a funtion of time t in terms of k, F, and m.

    I tried using F=ma:

    a= (F-kv)/m

    Then I integrated this from 0 to t and got


    I know that these answers can't be right, since this would be the same result if I had used the equation for constant acceleration. And its not constant acceleration, I'm not sure how to do this.

  2. jcsd
  3. May 1, 2007 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    When you integrate the velocity with respect to time, the result isn't velocity multiplied by time.
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