• Unknown1234_5@lemmy.world
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    3 days ago

    Ik this is a joke but if anyone is wondering it’s because units of linear motion (km/h, mph, etc.) do not accurately describe rotation. Rotational units like rpm are much better as linear units give a misleadingly large (though technically correct) number.

    • GoodEye8@lemm.ee
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      3 days ago

      If anyone is wondering it’s actually because of frame of reference. The first two images have speeds in relation to the rotation of earth, the last imagine uses a different frame of reference. If you put the last image in the same frame of reference as the first two images the number there would be 0km/h, because it would be moving in relation to itself.

      • mkwt@lemmy.world
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        3 days ago

        It’s actually because the thing that makes you make those faces is the acceleration, not the speed.

        All three reference frames shown are accelerated, non inertial frames. But the first two have “fictitious” centrifugal accelerations somewhere around 0.5-2.5 g. The third frame has a detectable centrifugal acceleration, but it’s like 0.003 g or something, and can be lumped in with gravity for many types of problems.