A dairy farmer who, in a fit of desperation over the fact that his cows don't give enough milk, consults a theoretical physicist about the problem. The physicist listens to him, asks a few questions, and then says he'll take the assignment. A few weeks later, he calls up the farmer, and says "I've got the answer." They arrange for him to give a presentation of his solution to the milk shortage. When the day for the presentation arrives, he begins his talk by saying, "First, let us assume a spherical cow..."
Last revision 24. September, 2005.