How Gears Trade Speed for Force

In the picture

1. 1Hand crank: your effort goes in here
2. 2Small driving gear: turns fast, in one direction
3. 3Large driven gear: turns slowly, the opposite way, with more turning force
4. 4Heavy bucket: lifted thanks to the extra turning force

Examples

• Shifting a bike to its smallest front gear makes it easy to pedal uphill, even though you go slower.
• A hand drill or egg beater uses meshing gears that turn in opposite directions.

Quiz: How Gears Trade Speed for Force (Age 13)

1. 1

   Two gears are meshed together. If the first gear turns clockwise, how does the second gear turn?

   • Anticlockwise, the opposite way to the first gear
   • It depends on which gear is bigger
   • Clockwise, the same way as the first gear
2. 2

   A small gear drives a bigger gear. What happens to the bigger gear?

   • It turns faster but with less turning force
   • It turns more slowly but with more turning force
   • It turns faster and with more turning force
3. 3

   Why does a small gear driving a big gear make a heavy job, like lifting a load, easier?

   • The big gear turns the same way as the small gear, so no effort is wasted
   • The big gear turns faster, so the load goes up quickly
   • The big gear turns with more turning force, even though it turns more slowly

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.