Gary Coffman wrote:

On 05 Oct 2003 02:31:09 GMT, a (Dave Baker) wrote:
... However, If we do 10
units of work to the object by moving it in a particular direction and then
another 10 moving it back again the net work is always 20 units ...

... negative work was done so that net work is
also zero? ...

The problem here is that work is a RATE (of energy). You can't, or
don't want to, talk about the conservation of a rate (work). The "...
work to the object by moving it ..." is meaningless. You want to talk
about the ENERGY to move the object. I could use 10,000 HP to move it
one direction and .01 HP to move it back.

Bob