A Train Floating On Air A train that floats on air? It's not magic―it's magnets
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A Train Floating On Air
A train that floats on air? It's notmagic―it's magnets (磁). And it's close to reality.
InVirginia USA the fall of 2002, a train with no wheels traveled on air andcarried college students across their campus. In Japan, a whisper-quiet railway engine hovered and raced at350 miles per hour using magnets and electricity as the power. And in China, a magnet train line linked Shanghai with nearby Pudong Airport.
These trains use magnetic levitation (悬浮) technology, “maglev” for short. They use the same rules asthe magnets you pick up at home or school: opposite poles of magnets attract each other, and like poles repeleach other.
How does it work?
Powerful magnets on the bottom of the trainrepel magnets on the track, which is actually just a magnet-filled guiding way.With a magnetic field of sufficient force, the train will go hovering on air, which seemed impossible tous in the past.
When an electrical current is sent throughthe track, the train moves. Turn the current backwards and the train slowsdown.
Maglev doesn't rely on the friction (摩擦力) of wheels on track, so it can climb a much steeper hill than a traditional train.And it can travel easily in snow and ice, something that could bring normaltrains to a screaming stop.
1.This passage is about __________.
A. maglev B. magnets C.levitation D. electricity
2.Which of the following is a repellingaction?
3.What can we learn from the text?
A. Amagnet-filled guiding way is formed inside a maglev train.
B. Instead of electricity, magnets are used as the power of a maglev.
C. Maglev trains can climb hills with the help of magnet wheels.
D. Electric currents decide the movements of a maglev train.
4.What is the difference between amaglev train and an ordinary train?
A. A maglev train can climb mountains without power while an ordinary onecan’t.
B. A maglev train can travel in college campus while an ordinary train is notallowed.
C. Travelling without a track, a maglevtrain is safer and smoother than an ordinary one.
D. Floatingon a track, a maglev train is faster, quieter than an ordinary railway train.
试题答案
【答案】
1.A
2.B
3.D
4.D