The rotation of the differential pinions makes the outside gear speed up.

You can actually shift your daily alertness cycle by going to bed earlier, he suggests. Another way to gear up in the morning is to go outside into the daylight as early as possible after you wake up.

Some cars have variable-ratio steering, which uses a rack-and-pinion gear set that has a different tooth pitch (number of teeth per inch) in the center than it has on the outside.