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B Two very basic questions about momentum in space

  1. Jan 9, 2017 #1
    This first question of mine is about momentum?
    And opposite forses.

    Lets think we have two batteries or something similar
    spinning in space like in carusel structure.
    And the batteries are athe more spinning end.
    First the batteries are empty and we start loading
    the first battery.
    So em i wrong that now this battery weight goes up?
    And what happens to this spinning thing

    And what happens when now we move the energy
    to this second battery from this first one?

    I ask this because there is suppoust to be
    any momentum but maybe a change in spin
    axix or not? So how the Newtons momentum
    should understand in electric changes?

    And the second question of mine is this.

    If we make a electromagnetic field and
    we alter this field by other field like some
    emitter or like. And this first field
    is at rapid on and of pulse
    can we make momentum?
    So if we think some kind of
    vehicle and so can we move it in
    this field in space or can we move this field
    for momentum?

    If someone can give me some basic real answer
    I would be happy!
     
  2. jcsd
  3. Jan 9, 2017 #2

    berkeman

    User Avatar

    Staff: Mentor

    Welcome to the PF.

    The work being done will change the center of mass of the rotating object, so it will just rotate a bit off of its geometric center. Just as if you had a person in the middle of the rotating object, and they did some work to pull part of the mass at one end of the rotating structure toward them. That only changes the center of mass (COM) and hence the center of rotation.
    It sounds like you are asking about EM Drives or Reactionless Drives, which are forbidden topics here. Please be sure to read the PF Rules under INFO at the top of the page, as well as the EM Drive link below. Thank you.

    https://www.physicsforums.com/threads/emdrive-revisited.338268/
     
  4. Jan 9, 2017 #3
    Ok! First sorry if this second question was at forbitten topics. So I leave this out.
     
  5. Jan 9, 2017 #4
    Ok! I am sorry if this second question was off- topic
    by this EmDrive forbitten issue. Sorry about that.

    So did i get this right that in this battery scenario
    it is possible to move mass to this second battery
    without making newton momentum forse to other
    x-y-z scale? But if in space we try to move mass
    in like common movement there happens x-y-z movement
    if this mass is not in vacum?

    So if first we have some axeled things
    and in these two we have battery we can choose
    in space withc keeps like in still and witch one moves
    in this scenario?

    And I hope this post gomes to right place pecause I am
    legally Blind and this is quite hard to me to focus
    tthese all things at this html page. So sorry if this
    is at wrong area or something like.

    But this battery scenario is to me little tricky
    and i like to think about these kind of topics.

    Thanks for answer
     
  6. Jan 9, 2017 #5

    berkeman

    User Avatar

    Staff: Mentor

    It still sounds like you are talking about Reactionless Drives. Have a look at this wikipedia page to see if it helps to answer your questions:

    https://en.wikipedia.org/wiki/Reactionless_drive

    :smile:
     
  7. Jan 9, 2017 #6
    Ok!
    But do you remember this thing that has axle and
    wings one side black and other side silver or aluminium like?

    Now lets forget the axle and think that this is at space
    and sun is bursting to this thing.. So it starts to rotate
    by its axis or em i totally wrong?

    And now lets image that in both sides at the point
    the sping is higher are batteries. So now if we load
    this other end that is not having the maximum light effect
    we load its battery the mass point change to this point and
    the rotation point can be alterted?

    And if I have understood correctl. Now we can move this
    thing in some where we need?

    And this is not a Emdrive or something like this but
    more like ship in wind that has stability more than lability?

    Or does this thing stay put and only moves out of the sun to
    pointles cordination?

    By the way and sidemark. Do you work at 50mc band?

    But as endmark has this mass change any relevant profit
    or does the newtons law to cut this benefit if there is
    working idea at all?

    Thanks for advice
     
  8. Jan 9, 2017 #7

    berkeman

    User Avatar

    Staff: Mentor

    Thread closed temporarily for Moderation...
     
  9. Jan 9, 2017 #8

    PeterDonis

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    2016 Award

    Staff: Mentor

    Do you mean the Crookes radiometer?

    https://en.wikipedia.org/wiki/Crookes_radiometer

    If so, you should read the Wikipedia page carefully, particularly the section on "effect observations".

    It won't rotate in a hard enough vacuum; see the Wikipedia page.
     
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