Firefighter Practice Exam

If Gear 1 is turning at 400 rpm, how quickly will Gear 2 turn?

1. The same speed

2. Twice as fast

3. Three times as fast

4. 20% faster

The correct answer is: The same speed

When two gears are engaged, their rotational speeds are related to their sizes (number of teeth) and the nature of their engagement. If Gear 1 is turning at 400 revolutions per minute (rpm) and Gear 2 is directly engaged with it, the speed at which Gear 2 turns will depend on its size relative to Gear 1. If Gear 2 is of the same size and has the same number of teeth as Gear 1, it will indeed turn at the same speed of 400 rpm. This demonstrates the principle that engaged gears with an equal number of teeth will maintain a 1:1 speed ratio, resulting in Gear 2 turning at the same speed as Gear 1. Understanding this fundamental relationship between gears is crucial in mechanical systems, as it allows predictions about how motion is transferred in gear trains.