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Homework Help: Force given velocity as function of space.

  1. Sep 2, 2015 #1
    1. The problem statement, all variables and given/known data
    The speed of a particle of mass m varies with space as v(x) =ax^-n
    v(x=0)=0 at t=0.
    Find F(x).

    2. Relevant equations
    F=ma=m dv/dt

    3. The attempt at a solution
    I am not really sure where to start from. Would x(t) or f(t) be relevant?
  2. jcsd
  3. Sep 2, 2015 #2
    You have Newton's law defining the relationship between the force and the acceleration. You also have the velocity as a function of time. Now you need the acceleration. And you can plug that in for the force.
  4. Sep 2, 2015 #3
    No we do not have velocity as a function of time, we have it as a function of space. Therefore we can't just differentiate and get the accel.
  5. Sep 2, 2015 #4
    Usually, these problems make use of the chain rule of differentiation.
  6. Sep 2, 2015 #5
    Is "a" acceleration or just a constant in the equation?
  7. Sep 2, 2015 #6
    Try rearranging dv/dt
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