Water is easily evaporated, and oil and grease will not evaporate.
The boiling of water is 100°, while the boiling point of lubricating oil is anywhere from 370°-600°. So oil is used because if the machine gets too hot, then the water may boil off, which will make the machine lose its lubrication.
prolly a beacuse the momentuem the car has increases while going down hill
their crystal patterns have been disrupted by stress