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Homework Help: Equations of motion

  1. Nov 9, 2006 #1
    The problem is to determine the equation of motion for a point particle on which both the gravitational force and a friction force of magnitude
    [tex]|\vec{F}_fr| = k|\vec{v}|[/tex]
    act and to show that when the particle starts at rest, its velocity cannot exceed mg/k.
    I have attached my calculations but something is wrong. The velocity cannot increase when the incline is almost flat..?
    Last edited: Nov 9, 2006
  2. jcsd
  3. Nov 9, 2006 #2


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    Incline? You can't be on an incline since additionally, there is a normal force. The problem makes no mention of such thing.

    Just solve the equation of motion for F=Fgrav-kv. Plug in the initial value v0=0 and show that v(t) is a monotonous function that converge assymptotically towards mg/k as t-->+infty.
  4. Nov 9, 2006 #3
    Of course. Thanks :)
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