1 The magnitude of a velocity vector is the rate of motion, usually measured in millimeters per year.  The direction of a velocity vector usually shows only the horizontal velocity. A vector is described in three dimensions: east-west, north-south, and up or down.
The cycle of eating and brushing can get tricky if you don't need to wait to eat after you brush, and then you brush after you eat -- over and over again during the day. If you eat sugary or acidic foods or drinks, the enamel on your teeth will be softened. Therefore, brushing right after you eat may not be wise. Dr. Rolfe explains that if you just had an acidic or sugary snack, you should gargle with a fluoride mouthwash and not brush your teeth.
All those who disagree and say it is permissible, then I tell you, if this was permissible, then women tasting food while fasting to check the salt is no different than brushing teeth with toothpaste and not swallowing.