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: Physics definition of work



Hi Tony:
My demo is traditional and very effective. A fixed pulley is
attached to a horizontal bar, about 1 meter above the table
ot floor. A string is suspended from it on both sides; make
a little drawing as you read this. The left side of the string
is attached to an object A, for example, 1 kg. The right
side of the string loops over a suspended pulley and is
connected to the same horizontal bar.

Another object B, for example, 2 kg, is suspended from
the axis of the suspended pulley. Adjust the length of the
string (or the elevation of the bar) so that both A and B
are suspended; they "balance each other". How can it be,
I ask, that an object A, whose mass is 1 kg is able to
balance an object B whose mass (and weight) is twice
as large? Then we talk about this apparent "paradox".
Sooner or later somebody would realize that B is only
partially supported by A; the other part of the supported
is the string attached to the bar.
Ludwik Kowalski

Tony Wayne wrote:

I'm doing a unit for the first time (in 16 years) on simple machines. Does
anyone have any cool demonstrations/labs or factoids relating to any simple
machine concepts?
-tony