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How do a bicycle's gears work?
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Working the pedals of a bicycle causes a chain to turn cogs on the back wheel. When a cyclist changes gear, a lever lifts the chain from one cog-wheel to another. Small cogs allow the back wheel to turn quickly, making it easier to cycle fast or uphill. Large cogs make the back wheel turn more slowly, which is useful when cycling downhill. | | A modern all-terrain bike has an average of 21 gears. This helps the rider to get up steep hills. |
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Previous:
Back
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Book:
1001
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Section:
Science and Technology
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Chapter:
Machines
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