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Homework Help: Gear ratio requirement (RPM --> km/h)

  1. Feb 6, 2015 #1
    1. The problem statement, all variables and given/known data
    A vehicle having wheels with a diameter of 58cm, is powered by motors that have a maximum speed of 6024 rpm. Each motor is coupled to the wheel using a gear mechanism as shown in figure 2-14. Calculate the required gear ratio if the vehicle's maximum speed is 190.2 km/hr.

    Note: Answer is a unitless value, correct upto two decimals.

    2. Relevant equations
    No clue. C = 2 * PI * R?

    3. The attempt at a solution
    I converted 6024 rpm to radians per second hoping I could do the same with hm/hr, but I do not know the radius of the tire? See photo attache for diagram. Thanks for help.

    Attached Files:

  2. jcsd
  3. Feb 6, 2015 #2

    Quantum Defect

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    ... but you know the diameter of the wheel. How is diameter related to radius?...
  4. Feb 6, 2015 #3


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    I would start "at the other end of the problem". eg Work out the rpm of the wheel at max velocity.
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