< User:Kingturtle
Political theory
World War II
Cold War Part One (of Three) (1945-1963)
==Cold War (part two of three) ((1964-1980)
Race outline
Psychology topics
Personalities in U.S. History
Presidents
Mythology
... "rolling" inside the groove. (Compare with graphic below.) Since this friction force is essential for the device's operation, the groove must not be lubricated. Th ...