• lsd@lemmy.world
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      6 months ago

      The magnet is not pulling the car, the hand holding the magnet is pulling the car.

      • farfarawaay@sh.itjust.works
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        6 months ago

        Okay. Maybe even dumb it down a little more? Just in case someone out there still doesn’t get it. Not me, I get it. Just someone else might not, and what about them you know?!

        • rockSlayer@lemmy.world
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          6 months ago

          When the magnet got glued to the car, it became part of the car so it wouldn’t actually move. The reason it moves when it isn’t glued is because the hand keeps pulling the magnet away

        • MotoAsh@lemmy.world
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          6 months ago

          Magnets transmit force, they don’t magically create energy. It takes energy to move the car, not just a static force being present. It’s the same as taping a stick to it without the magnets. Unless someone pulls on the stick (or magnet), no energy is entering the system and no work can be done.

        • gedaliyah@lemmy.world
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          6 months ago

          Imagine a string instead of two magnets. If the hand pulls the string, the car moves. If the string is tied to the car?

        • benignintervention@lemmy.world
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          6 months ago

          Time to draw some free body diagrams!

          Actually it would be the same force on the car if you removed the arm holding the magnet and placed a block of wood in the space between the magnets. It’s a static system

        • kyle1320@lemmy.world
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          6 months ago

          Just like the hanging magnet is pulling on the car, the car magnet is also pulling on the hanging apparatus. Unfortunately for the car, the apparatus is attached to it, so it all cancels out.

    • MystikIncarnate@lemmy.ca
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      6 months ago

      Basically, as much as the magnet on the car is pushing it forward, the magnet on the stick is pulling it back and it doesn’t go anywhere.

    • Jerkface@lemmy.world
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      6 months ago

      I know there are a lot of replies already, but I feel like the best way to explain is it’s similar to trying to push a car while you’re in it.

      • kwirky@lemmy.ca
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        6 months ago

        I haven’t been able to locate the link again, but the full video shows they’re using a hairdryer to push it.

    • Rentlar@lemmy.ca
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      6 months ago

      In simplest terms, the two magnets are trying to pull toward each other equally. But when you glue them on the board, that glue holds the magnets apart, and “pushes” them the same amount that the magnets “pull” towards each other, hence no movement.

      There would only be a movement if one side was pulling more than the other. The hand is providing that imbalance at first which moved the car.

    • Match!!@pawb.social
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      6 months ago

      It doesn’t work because, while the front magnet is pulling the car magnet forward, the car magnet is also pulling the front magnet backwards and the front magnet is also attached to the car, so it cancels out.

    • Annoyed_🦀 🏅@monyet.cc
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      6 months ago

      Magnet want to pull and stick to each other of the different pole. When it glued to the car, the one on the cardboard will want to move toward the car and the one on the front hood will want to move toward the cardboard. The force cancel each other out so no movement will happen.

    • Slow@lemmy.today
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      6 months ago

      I think it’s the same as trying to give a sailboat acceleration by trying to blow the sails while standing on deck.

      • lemmefixdat4u@lemmy.world
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        6 months ago

        Not quite the same as the two magnets. If you have a big fan and a square sail, you’re moving air, which has mass and is not attached to the boat. That alone will cause a force that moves the boat backwards. The moving air that hits the sail will not fully cancel that force due to frictional losses and air spillage from the edges.

        Racing yachts are a different story. They have rigid sails that are shaped like airfoils. Blowing across an airfoil causes lift. So a big fan blowing perpendicular to the axis of the boat across such a sail would move the boat forward. But it’s much more efficient for the fan to blow backwards without the sail, hence airboats and hovercraft.

      • JohnSwanFromTheLough@lemmy.world
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        6 months ago

        If you could scale the strength of blowing all the way up this would actually work though no?

        For example, if you were in a light kayak with a mini sail and had a high powered leaf blower pointing at the sail, would that work?

        • gerryflap@feddit.nl
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          6 months ago

          If you’d blow with a leaf blower or something to the front of the boat, the boat might actually go backwards of there’s enough force. The leaf blower is basically pushing the air forwards, therefore it’s also pushing itself backwards. Some go this will probably be cancelled by blowing against the sail, but some air will also pass around it.

    • Johanno@lemmynsfw.com
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      6 months ago

      Ok when not glued: both magnets get pulled to each other. The hand has to use some force in order to stay in place, so the car moves.

      When glued: both magnets still get pulled to each other, but now the force is cancelled out since the force that would pull it forward also has to be used to hold the other in place.

  • Seeker@infosec.pub
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    6 months ago

    No one is commenting about the magnet on the back of the car and possibly a magnet in the person’s hand causing the rear magnet to repel against the hand magnet?

  • LemmyKnowsBest@lemmy.world
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    6 months ago

    okay but I bet the same concept would work if the distant magnet mounted on a plank from the top of the toy was on some sort of a crank mechanism that moved it rhythmically away and near and away and near from the other magnet.

    Granted that wouldn’t accomplish the objective of perpetual motion because that crank mechanism would require its own power source like a battery.

    So if that hypothetical crank mechanism would need a battery, might as well cut out the middleman and leave out the magnets, and power the car with a battery.