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Homework Help: Tangential acceleration - radial acceleration

  1. Apr 17, 2012 #1

    I got a ball in a circualar motion on a frictionless table and in a uniform circle.
    I need to calculate the tangential acceleration and radial acceleration.

    What I know:

    Radius: 0.4m
    Tangential velocity: 0.50m/s^-1 (constant)

    Are theese formulas right for this problem?

    Radial acceleration = V^2 / r

    Tangential acceleration = r*angular acceleration

    Because I am confused when I mix tangential velocity with radial acceleration and so on.. and I need some help on how I can calculate the angula acceleration for the tangential acceleration.

    Every bit of information would help alot!

  2. jcsd
  3. Apr 17, 2012 #2
    The tangential accelearation of a constant tangential velocity is always zero, because the change in velocity is zero. The formula for radial part is:
    [itex] \alpha = \dfrac{\text{d}\omega}{\text{d}t} = \dfrac{\text{d}^2\theta}{\text{d}t^2}[/itex]
    And for tangential :
    [itex] \vec{a} = \dfrac{\text{d}\vec{v}}{\text{d}t} = \dfrac{\text{d}^2\vec{r}}{\text{d}t^2}[/itex]
  4. Apr 17, 2012 #3
    Thanks that solved it for me;)
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