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Gyroscope

A gyroscope is a wheel that resists being tipped over when it is spinning very fast.

Water wheel

A water wheel is a wheel turned by running water in a river to operate a machinę.

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Alrllner wheels

Aircraft wheels and tires have to be very strong

to land a piane safely.

01: When a large piane touches down, its main wheels spin from 0 to 155 mph (250 kph) in a fraction of a second.

02: A puff of smoke from the tires shows the moment that the wheels touch the ground.

03: The nose wheel of a Boeing 737 is around the same size as a car wheel. It's designed to go faster than a racecar while holding up the weight of three family-size cars.

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Some wheels are great fun

^ M Ferris wheels like w A the London Eye and the Singapore Flyer take you high up into the sky and back down to Earth.

Playground

\3km roundabouts whirl you around and around as fast as you like.

Bikes are a fun w O way to get around, if you can keep your balance.

/>/■ Skateboards are wnl great for stunts and jumps.

Roller skates put w w wheels on your feet. Quads have two wheels in front and two at the back, while rollerblades have up to five wheels in a linę.

A Catherine wheel w w is a wheel-shaped firework that spins around when it is lit.

Tell me morę:

changing a racecar wheel

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7.0 seconds The fuel hose is pulled away from the car.

7.3 seconds The lollipop man lifts his or her sign and the driver sets off.

It takes less than ten seconds to | change the wheels of a racecar.

0.0 seconds The moment that the car stops in the pits, around 20 mechanics swarm around it. One mechanic, called the lollipop man or woman, holds a “Brakes on” sign in front of the car to remind the driver to keep a foot on the brakes.

0.2 seconds A mechanic at each wheel uses an air-powered wrench to remove the single nut that holds on each wheel.

1.0 seconds The car is jacked up off the ground by mechanics at the front and back.

1.5 seconds The old wheels are pulled off, and new ones are pushed on.

jc2.5 seconds While the wheels are being changed, a fuel hose is connected to the car to fili up its fuel tank.

3.5 seconds Mechanics tighten the wheel nuts, and the jacks are lowered.

3.8 seconds The lollipop man or woman shows the driver a sign to put the car in first gear. A mechanic cleans his or her helmet visor.

(c) 2011 Dorling Kindersley. Ali Rights Reserved