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] |
only
A block slides to rest along a level rough table. The only net force
on the block is kinetic friction. The table is clamped to the floor
and hence to the earth. We approximate the earth as being an inertial
system. The observer is at rest with respect to the table. I hope
this is clear. Now for the question:
HOW MUCH WORK DID THE BLOCK DO ON THE TABLE?
Well, Carl, you suggest and impossible situation and then give as the
answers wrong results.how
In this proposed case the Earth is not an inertial system -- no matter
closely it approximates one. OK I give you no rotation if you likefor the
nonce but the Earth/table moves with respect to the CM of theEarth/block
system.faulty
And then you adopt the invention of pseudowork to deal with this
proposal.that
The block does work on the Earth = negative work done on the block.
This is the same question as the ice skater pushing off and requiring
the rink be an inertial system and thus the work done on the rink = 0.It
is not = 0
Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen