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.
I'd encourage people to brush after lunch as well. If you brush at eight in the morning and go to bed at 10 or 11 at night, you've got 14 or 15 hours of eating, for bacteria to build up.. But too much brushing, with bad technique, can cause other problems.