This article was updated Feb. 28, 2023. It was originally published March 1, 2000. Planetary gears can supply high levels of torque and high-speed reduction. They are also relatively compact compared ...

The film *Spinning Levers* explores the fundamental mechanics of levers and gears, illustrating their role in various everyday applications and in the complex workings of a car’s transmission.

Admit it, before a run you waste time fussing over your outfit. Does this top go with these shorts? Do those Union Jack shorts go with anything? To keep these fashion dilemmas to a minimum, buy ...