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Footprints in the Sand.

  1. Nov 30, 2013 #1


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    Is it true, that when you walk towards the West through a sandy desert, your footprints are deeper on average than when you walk towards the East.
  2. jcsd
  3. Nov 30, 2013 #2


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    I can't imagine why they would be? Where did you hear this?
  4. Nov 30, 2013 #3

    Simon Bridge

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    Probably not to the accuracy that you can measure the depth of footprints in sand whose surface does not conform to the average curvature of the Earth anyway.

    Similarly - water does not spiral a different way down the plughole in the north and south latitudes.. simply because there are so many different things that have a bigger contribution to the phenomena.

    However, what you are talking about is the effect of being in a non-inertial frame: the Earth is spinning.
    When you travel at a constant speed around the Earth, too, you are slightly changing direction according to the curvature of the Earth.

    You want to look up the coriolis and centrifugal effects.
  5. Nov 30, 2013 #4


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    What simon bridge said, about the centrifugal effect. (I don't think the coriolis effect would make any difference to the question).

    But it would be unmeasurably small. If you were traveling along the equator at about 1000 miles/hour, your effective weight would change by less than 1% depending whether you were going east or west.
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