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How many of you look at the Physics Challenges in TPT? Well, anyhow,It might be helpful to know if the ratio of masses is greater or less than the ratio
go look at the October challenge and its solution at:
http://scitation.aip.org/journals/doc/PHTEAH-home/challenges/oct2010.pdf
I find myself in a bit of disagreement over the parenthetical note at
the beginning of Case 2 which is supposed to explain that the heavy
block can never slip on the ribbon.
I agree that both blocks cannot continuously slip (unless we allow
the ribbon to bunch up near the top of the prism!). But I think that
for steep angles, either block could slip. For the sake of argument,
suppose I initially force the light block to move with the ribbon (by
some unspecified coupler) but allow the heavy block to slip on it. If
I now release the light block coupling, there's no reason it'll
suddenly start slipping. Once started with the heavy block slipping
and the light block moving with the ribbon, that configuration is
stable.
So what happens when the two blocks are "simultaneously" released
depends sensitively on the exact details of the starting conditions.
I think it's like putting a pencil on point and asking which way
it'll fall. Who knows!
But I'm interested to hear what others think. Careful though: think
about it first or this could turn into another endless buoyancy
thread.... Carl