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3

The truth is told by because


1

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 ...


32



-1

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, ...


2

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 ...


17

My instinct is that: This is based on:


10

Reductio ad absurdum


3

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


3

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


12

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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