Popular: If it is October 5th, at approximately what latitude would you have to be in order to see the sun directly overhead at noon? What events occur when an electron in the excited state returns to its ground state? Are all endergonic reactions also anabolic? I need to know details about stone tumbling machines. and need to know what types of stones, rocks i can work with using a tumbler.? (y^2-x^2)dx+xydy=0?