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Gravitational Field

  1. Nov 5, 2015 #1
    Hi guys!

    What would happen to objects on the Earth's surface if it SLOWLY stopped spinning and Earth's gravitational field was kept as always.

    Thx
     
  2. jcsd
  3. Nov 5, 2015 #2

    davenn

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    Hi welcome to PF

    what do you think would happen ?
    consider the difference of when you are in a car that stops quickly or slowly


    Dave
     
  4. Nov 5, 2015 #3
    Considering earths dimension, if it lost the angular momentum slowly due to somenthing we woundn't notice, right?
     
  5. Nov 5, 2015 #4

    davenn

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    correct ...

    Im not sure of the maths offhand, maybe some one else can chime in and
    give info on how slow the deceleration would be before it wasn't noticeable
     
  6. Nov 5, 2015 #5

    jbriggs444

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    The Earth's rotation is slowing and we have noticed.
     
  7. Nov 5, 2015 #6
    Yeah, different meanings of "noticeable". :)
     
  8. Nov 5, 2015 #7

    davenn

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    indeed as with good instruments

    uh huh
    so I wonder what would be the necessary deceleration to be humanly noticeable to the avg person ?

    0.2 - 0.5g is easily noticeable with earthquake motion
     
  9. Nov 5, 2015 #8

    jbriggs444

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    Can you imagine the kind of ocean current you could get from something as tiny as 0.01 g? Goodbye, California.
     
  10. Nov 6, 2015 #9

    sophiecentaur

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    The centripetal force needed to keep an object of mass m on a circular path of radius r and at a speed v is given by F = mv2/r
    Put in the numbers for an object of 1kg on the Earths Equator and the speed (all that data is readily available) and you can calculate the force. Compare that with the weight force (approximately 10N per kg) and that will tell you whether or not we would "notice" it. It will relate to the difference in the Weight of an object at the N Pole and at the Equator.

    You could also, using the SUVAT equations, find out how quickly you could bring the Earth's rotation to a halt if you wanted the effect to be 1. Noticeable and 2. low enough so that things don't go flying off the table or buildings topple over. You can make up your own numbers for the acceleration (negative acceleration, of course) for those two conditions i.e how much g force?

    It's just as well that it's not an experiment that we could ever do. If it were possible then some damned fool could just possibly try it. :))
     
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