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Homework Help: Rotational kinematics of analog clock

  1. Nov 5, 2008 #1
    When it is 10:00, the hour hand on an analog clock is 300 ahead of the minute hand. How many minutes elapse (to three significant digits) before the minute hand next points in the same direction as the hour hand?

    I seems really easy, but for some reason I am not getting the right answer.

    Can I use rotational kinematics?
  2. jcsd
  3. Nov 5, 2008 #2


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    Homework Helper

    Re: Rotation

    Looks like a logic problem.

    Write an equation for the motion of the hands of a clock. What is the speed of the hour hand? What is the speed of the minute hand.

    Then figure the next time the hands have the opportunity to be 300 degrees apart again and create an equation that takes into account the effect of both the hand in getting to be exactly 300 degrees apart.
  4. Nov 5, 2008 #3
    Re: Rotation

    First of all, think what is the next time after 10.00 where the two hands of a clock are on top of each other? That's essentially your answer - the only time the hands of a clock are pointing in the same direction is when they're on top of one another.
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