Physics and Free Software

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Cake day: June 5th, 2023

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  • Fun fact. The United States is and always will be 1st world by definition. The 'Three Worlds ’ model comes down to the cold war where a country is aligned with the United States, the Soviet Union, or neutral. Switzerland is a 3rd world country. What people generally call the third world is better describe as ‘global south’, and they either ignore 1st and 2nd world completely or neglect the 2nd world completely and call themselves the 1st world. With regard to the United States I think you mean it’s becoming the biggest fucking piece of shit country, or you might mean it is no longer aligned with itself, plans to leave NATO, is not aligned with the soviet union, and is then by definition the largest 3rd world country.



  • wuphysics87@lemmy.mltoMemes@lemmy.mlTrickflation
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    18 days ago

    It’s not really ‘right’ or ‘wrong’ it’s under a fixed set of assumptions. You raise a valid point. What does happen to the top and the bottom? I was ignoring them considering only the sides in the two most extreme cases.

    If I understand your case when the can is flatted the area gets much larger and when it gets taller it shrinks to a pin point. An equally valid approach


  • wuphysics87@lemmy.mltoMemes@lemmy.mlTrickflation
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    18 days ago

    Quick ‘proof’ the taller the can, the more material used:

    Consider two cases ignoring the top and bottom only focussing on the surface area. In the first case, you flatten so much the can has no height. This forms a ring that when unwrapped makes a length of 2 pi R.

    Now stretch the can to be ‘infinitely’ long. By construction, this is longer than 2 pi r. Given both are made of aluminum, and have the same density, the larger can has more mass requiring more material.

    The total mass must be a continuous function ranging from the linear mass density times the circumference of the circle to the same mass density time times the ‘length’ of the infinite line. This must remain true for any small increase in length between the two.

    I’ll leave this as an exercise to the reader. What if the circle has an infinite radius?