A centripetal force (from Latin centrum center and petere to seek) is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path.
There are a number of things that can cause a whitish coating or white spots to develop on the tongue, including the f ollowing: 1  Leukoplakia. 2  Oral thrush. 3  Oral lichen planus.
Tongue injuries (piercings and dental appliances) are a possible cause of black patches on your tongue especially if the injury cause sores. You can also end up with dark spots on tongue from biting or after biting your tongue. Anemia. Anemia is another possible cause of black tongue spots. Many people have reported this problem.