> <<<<< If you have a toy boat in the bathtub, filled with nuts and bolts,
> and you tip the boat over, dumping its cargo to the bottom of the
> tub, what happens to the water level in the tub? (note, the boat
> returns to it original floating position and takes on no water.) >>>>
>
> Answer: the water level drops (less water is displaced -- as before the
> weight of water displaced equals the weight of the cargo and boat,
> afterwards, the amount of water displaced is the weight of the boat plus
> the volume of the cargo and as water is less dense than the cargo.....)
>
> <<<<<< Also,
> I give you two cylinders, both identical in appearance and weight.
> One is made of aluminum, and is solid. The other is made of gold,
> and has the center hollowed out (outside surfaces are unbroken,
> however.) Both are painted an identical non-conducting British
> Racing Green (obligatory lame attempt at LBC content).
> Performing only non-destructive testing, with materials/methods
> available in the typical household, how can you tell which cylinder
> is which? Tapping on the cylinders with a mallet produces identical
> sounds.>>>>>>
>
> Easy : measure the rotary moment of intertia: ie. how much force will it
> take to make each object spin or stop spinning?
>
>
>
> Simon
>
>
> ---
Well, I was going to continue to take answers on these for a while
longer, and reply via private e-mail to the hardy souls that took a
shot at it, but since Simon has pegged both answers perfectly, and
explained them more concisely than I could, I'll save myself the
trouble of writing out the answers and just print his.
One addition to his answer for #2--The easiest "household" way to
measure the rotary moment of inertia is to roll both cylinders down
some kind of incline onto a long, flat surface. Since the gold
cylinder has more of its weight farther away from its longitudinal
axis, it will roll further after reaching the flat surface than the
aluminum one will.
Would anybody like me to occasionally post these types of questions,
or am I just being an off-topic pain in the a**? If you'd like, send
me an e-mail with the type of puzzles you like, and your
educational background/area of expertise, and I'm sure I can come up
with some tailored just for you.
Scott
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