Try a ratio, then a quiz

How do gears usually work?

Singly, like a leverIn pairs, without slipOnly in clocks

If the driven gear has twice as many teeth as the pinion, the driven gear…

Turns twice as fast, with half the turning forceTurns at the same speedTurns at half the speed, with twice the turning force

What is the pinion?

The smaller gear of a pairAny gear with curved teethThe shaft itself

How many teeth must a worm have?

At least fiveIt may have only one threadExactly twelve

Can a machine do more work than you put into it?

Yes, that is what mechanical advantage meansOnly if the gears are circularNo: energy is conserved

In Watt’s sun-and-planet gear, if both wheels are the same diameter, the fly-wheel…

Makes twice the revolutions of a simple crankMakes half the revolutions of a simple crankDoes not turn

What is the motion work in a clock?

The pendulum itselfA simple 12-to-1 gearing that drives the hour handThe winding square

Besides a normal speed equal to the chain sprocket, the 1906 Sturmey-Archer hub gives…

Two speeds, both higher than normalA 2-to-1 reduction onlyOne 31.25% above normal and one 23.8% below