In the descriptive sense, people speak of luck after events that they find to be fortunate or unfortunate, and maybe improbable. Therefore, cultural views of luck vary from perceiving luck as a matter of random chance to attributing to such explanations of faith or superstition.
Chirping can be due to misalignment of the drive belt, but could also be due to pulley misalignment, worn pulley bearings, worn belt ribs, contamination from oil, coolant, power steering fluid, brake cleaner, belt dressing, or other substances. Squealing is usually caused by slipping between the belt and the pulleys.
What causes the noise when you crack a joint? Escaping gases, movement and rough surfaces. Your joints can make a variety of sounds: popping, cracking, grinding, and snapping. The joints that crack are the knuckles, knees, ankles, back, and neck. There are different reasons why these joints sound off. Escaping gases: Scientists explain that synovial fluid present in your joints acts as a lubricant.