Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

Re: kinetic energy paradox?

In a message dated 10/24/2001 2:26:25 PM Eastern Daylight Time, mungan@USNA.EDU writes:


. But how about
the following then: if I have a spool (with a suitable moment of
inertia) and I pull on the thread at just the right angle, I can get
the spool to roll (starting from rest) even on a frictionless surface
(without slipping), can I not? (Sorry I couldn't resist bringing this
up ;-)

Which is to say, friction is not really required for rolling.
But you are assuming that while there may not be friction between the spool and the surface on which it is resting, there is friction between the thread and the spool.

Justin Parke