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  • Friction is what allows us to move

  • ...and to slow down.

  • Friction is how we pick things up

  • ...and hold on to them.

  • To be totally honest,

  • there isn't much we could do without friction!

  • A world without friction would be unlivable.

  • But, do you think you could function

  • for one minute without it?

  • The reason why friction is

  • so important to our world,

  • is because it affects everything that's in motion.

  • When any object is moving,

  • slipping or sliding in one direction,

  • friction is acting in the opposite direction.

  • So, for example, consider something

  • as simple as walking.

  • Your feet are pushing

  • backward against the ground,

  • and the ground reacts by pushing

  • forward on your foot,

  • allowing you to accelerate.

  • But it's a lot easier to walk on concrete

  • than it is to walk on ice, right?

  • That's because ice has a much lower

  • coefficient of friction than concrete.

  • In other words,

  • ice is much smoother than concrete,

  • so it has less resistance,

  • causing your feet to slip and slide.

  • The same example can be applied to vehicles.

  • In fact, car tires are designed

  • with friction in mind,

  • to optimize your safety, and to make sure that

  • you can turn and stop without skidding.

  • In dry conditions, having a tire

  • that's completely smooth

  • actually gives you better handling,

  • since there is more surface area

  • to generate frictional forces.

  • But the reason why your car's tires

  • probably have treads

  • is to improve traction in wet conditions.

  • When you're driving in rain or snow,

  • even a thin layer of water between the road

  • and your tire can cause you to lose control.

  • That's because there's less contact

  • between the tire and the road,

  • so the forces of friction can't work their magic!

  • But tires with treads have grooves

  • that divert the excess water,

  • so the rubber can connect with the road,

  • and you can drive safely.

  • Of course, there are plenty of other ways

  • to test how friction works.

  • Do some redecorating,

  • play a game of ice hockey,

  • or, light a match!

  • Yes, celebrate friction,

  • and be grateful it exists,

  • because you don't know what you've got

  • until it's gone for one minute.

  • Cut the fireworks.

  • Matches don't work any more,

  • and you can't use lighters.

  • In fact, you can't pick anything up,

  • because your ability to grip

  • and pick things up is due to friction.

  • Anything you were holding on to,

  • the moment friction ceased to exist,

  • would instantly fall to the ground

  • or fly out of your hand.

  • If you were walking when friction disappeared,

  • your legs would still work,

  • but you wouldn't go anywhere.

  • But if you were in a moving vehicle,

  • you'd keep going, and going,

  • and going, and going,

  • until you crashed into something!

  • Your brakes are friction.

  • In fact, for that one, seemingly endless,

  • minute of chaos and destruction,

  • terminal velocity would cease to exist,

  • meaning that anything in motion

  • would be a deadly projectile.

  • At least you wouldn't get rope burn...

  • But that tree, that penny,

  • that runaway train is

  • actually the least of your worries,

  • because within just one minute of losing friction

  • actually, within an instant of losing friction

  • the whole world would just become

  • one big, formless, featureless blob.

  • Considering that everything on Earth

  • is composed of atoms and particles,

  • and that all atoms and particles

  • are held together by friction,

  • If you've ever wondered why skidding cars

  • and baseball slides look so cool,

  • well, just be grateful for friction.

  • Yes, it can make life hard sometimes,

  • but, it beats losing literally

  • everything on this planet!

  • So go on, try it for yourself.

  • Take a walk, and feel the friction

  • between your feet and the ground.

  • But don't go too far!

  • Double back quickly for

  • another episode of "What If!"

Friction is what allows us to move

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B2 中高級

如果1分鐘內沒有摩擦力呢? (What If There Was No Friction for 1 Minute?)

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    林宜悉 發佈於 2021 年 01 月 14 日
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