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Homework Help: Uniform Circular Motion - Finding Linear Speed

  1. Mar 5, 2012 #1
    1. The problem statement, all variables and given/known data
    The Bohr model of the hydrogem atom has one electron rotating around its center.
    If it has a radius of 5.29 * 10-11 m. And the mass of the electron is : 9.11 * 10-31. And the electrostatic force between the orbiting electron and the center proton is 8.20 * 10-8.

    1) the centripetal acceleration of the electron
    2) The linear speed of the electron
    3) the period of the the electrons rotation

    2. Relevant equations
    t = 2 ∏ r / V

    3. The attempt at a solution
    Part 1 I managed to calculated. I got the correct answer of ac = 9.00 * 1022.

    I also found that Velocity is equal to 2182104.645 ms/s.

    However for the period and the linear speed im stuck.

    For the period I get:
    t = 2 ∏ r / V
    t = 1.52321 * 10-16

    ^according to the answer sheet this answer is wrong and should be, 4.82*10-16

    For the linear speed im stuck. What exactly am I finding? I have no idea what to do.
    ^ the apparent answer is 6.9 x 105

    NOTE: Answers may be wrong as this textbook often has incorrect answers.

  2. jcsd
  3. Mar 5, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi MohammadG! :smile:
    I suspect you've used the wrong numbers.

    Did you use v= √(ra) ?
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