Three Laws Control the World
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Three Laws Control the World
  • GLOBE
  • 승인 2014.03.12 12:08
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As we can’t live without science, we will introduce you to our brand new corner, ‘Science’. Don’t step back because of the word ‘science’. Actually, science doesn’t exist far away. We will look up several basic science principles around you. Reading science in The CBNU Globe will help you to get along with it.
In March, let’s talk about Newton’s law. Some of you might think, ‘Newton doesn’t have anything to do with me!’ However, Isaac Newton is considered one of the greatest scientists to have ever existed. Tons of theories are based on his principles that have led us to such a convenient world. There are three big laws from him, called Newton’s law. This is about the relationships between force and motion such as inertia, acceleration and action-reaction relation.

● The First Law: Inertia
Have you ever ridden a bus that stopped suddenly and made you lean forward? That’s the principal of inertia. Every object tends to remain in that state of motion unless an external force is applied to it. Objects keep on doing what they’re doing. Newton adopted the concept of inertia for the first time and this became a base for explaining the law of conservation of motion. You can see many examples of this law.
In summer, there is a fan running and when you turn it off, it doesn’t stop right at that moment. It takes a couple of turns to stop it. The wings want to remain running.
Let’s move on to the situation when you are in a dining room. To get ketchup out of the almost empty bottle, you have to shake it fast. The ketchup inside the bottle wants to stay at the bottom but shaking it hard makes it move forward. It’s the same principle in cleaning a blanket. You have to tap it harder and more rapidly to ease the dust. In these ways, you are applying the law of inertia in your life when you don’t even realize it.

● The Second Law: Acceleration
The second law is about acceleration. You may heard of the formula ‘F=MA’ at least once as it is really famous in physics. The letters stand for F for force, M for mass, and A for acceleration. Every object with a mass has force and it depends on the acceleration. If the object doesn’t move, which makes the acceleration zero, the force will be zero since multiplying zero with any number makes it zero. If there are same objects with the same mass, but moving with different changes of speed, the faster one has bigger force.
Which one do you feel is easier, slapping with a full-swing hand or just with a little bit of movement? Of course you will choose the latter. The mass of the hand is the same but the acceleration is variable.
It’s harder to stop Usain Bolt, the fastest man in the world, when he is running than when he is walking. Since his acceleration is incredibly high, this gives him a large amount of force. That’s why runners can’t stop right after they pass the finish line.

● The Third Law: Action and Reaction
This is also called interacting force. No one can see force, but this law tells us that all force pushes back. For every action, there is an equal amount and opposite reaction. To put it simply, you push the object, it pushes you back.
If you imagine how a rocket launches, you can figure out what it is. A rocket expels the gas to push against the ground and the ground pushes it back to rise. Also, when you are nailing toward the wall, the hammer gets the same force that the nail gets in the opposite direction. So the nail gets stuck in the wall and your hand gets a little bit of vibrating motion. Here is another funny example: When you hit your friend with your hand, your hand also gets red and hurts. So do not hit your friend too harshly, however angry you are!

Although the force is unable to be seen, it’s still around you. If this is the first time you’ve heard of Newton’s law, it could sound strange. Or maybe some of you might apply Newton’s law to real life without realizing it. However, thanks to Newton, his amazing work has been the base for development of technology and science. Through his organizing, these laws have been able to calculate the movement of moving things. You cannot see the movements are there, existing, but they have been there all the time. He found out these laws by observing movement around him, and therefore he brought us amazing developments such as rocket launching and car acceleration. After reading this article, why don’t you try finding another example of Newton’s law around you?


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