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Homework Help: What is its centripetal acceleration?

  1. Jun 30, 2010 #1
    1. The problem statement, all variables and given/known data
    (a) What is the tangential acceleration of a bug on the rim of a 8.0 in. diameter disk if the disk moves from rest to an angular speed of 77 rev/min in 3.0 s? (b) When the disk is at its final speed, what is the tangential velocity of the bug? (c) One second after the bug starts from rest, what is its tangential acceleration? What is its centripetal acceleration?


    2. Relevant equations
    ac= vT2 / R


    3. The attempt at a solution
    I got all of the answers in italics, I just can;t figure out the bold part.
    answers in italics:
    a. a=0.273 m/s2
    b. vT=0.819 m/s
    c. a=0.273 m/s2

    d. ac = 0.819 m/s 2 / 0.1016
    ac = 6.60 m/s2

    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 30, 2010 #2

    Doc Al

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    Staff: Mentor

    It's not clear to me what you did here. How do you calculate the centripetal acceleration? Hint: What's the speed of the bug at the point in question?
     
  4. Jun 30, 2010 #3
    i used the equation: ac= vT2 / R
     
  5. Jun 30, 2010 #4

    Doc Al

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    Staff: Mentor

    OK, good. What's the speed of the bug after one second? (Note that this is not the final speed you calculated in part b.)
     
  6. Jul 1, 2010 #5
     
  7. Jul 1, 2010 #6

    Doc Al

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    Staff: Mentor

    Part (a) was done correctly; she's asking about part (d), which does ask for centripetal acceleration.
     
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