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The truth is told by because


So long as the starting angle is close to that shown, the broom end hits the ground first. The question isn't ill-defined so much as requiring a bit of understanding about real-world broom handle lengths and how being a couple of feet off the ground to start with will make that initial angle much less than 47 degrees. Reason: The easiest way to think of it ...



For the moment, consider just the broom handle and the level at which it becomes horizontal: 1 - the tip of the handle and it's midpoint reach there at the same moment: the tip has travelled twice as far but at twice the speed. 2 - the keys must reach that level first. The only force on the keys is it's weight and it's acceleration is g. On the broom, ...


Assuming the end of the broom doesn't slide along the floor and neglecting air friction, I believe that: A is correct for an initial angle of the broom at 60 degrees. B is correct for initial angles greater than 60 degrees. C is correct for initial angles less than 60 degrees. My reasoning was: When the broom was almost upright it would start to ...


My instinct is that: This is based on:


Reductio ad absurdum


I'll post my own answer to the question, mainly so that I can highlight and explain some of the pitfalls of the puzzle.


The forces on the beaker+water system are and and So I think the scale will measure (I am adopting the convenient approximation, already present in the question itself, that the density of water is exactly 1g/cm^3, which isn't exactly right but is very close.) But that's not quite right because


Well it seems to me that Also, as @Daniel Mathias points out Therefore So the scale would read very close to

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