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B1 중급 영어 15:59 Educational

EASY Pinewood Derby Car WINS using Science!!!

Mark Rober · 33,115,286 조회수 · 추가됨 3주 전

학습 통계

B1

CEFR 레벨

5/10

난이도

자막 (237 세그먼트)

00:00

This is a Pinewood Derby car.

00:02

It comes in a kit, then you build it and put it together,

00:04

and then it uses gravity to go down a track.

00:06

So over 100 million of these cars have been built and raised by kids over the past 60 years.

00:11

Which means over 100 million dads have spent a lot of time at the workbench,

00:14

and then subsequently pretended their kid helped in some meaningful way.

00:17

But don't feel bad for the boys, because someday they'll grow up to be dads,

00:19

and then they'll get a chance to work on a car of their very own.

00:22

Now this is a much faster Pinewood Derby car.

00:25

But wait, this was my entry.

00:27

I was disqualified because apparently using jet propulsion goes against the spirit of the competition.

00:33

Let's roll!

00:42

This is a much faster legal car.

00:45

But what is it about this one that makes it so much faster than this one?

00:50

I mean really, is it the wheels? Is it the weight placement? Is it the axles?

00:54

And of the design features that influence speed, which one of those is the most important?

00:57

For example, do aerodynamics really play a role?

01:00

So today, we're going to use cold hard science to figure out how you can maximize your chance of taking home the trophy

01:05

with the least amount of effort.

01:07

There are a lot of opinions on how you build a fast car, and spoiler alert,

01:11

some of the most popular ones are completely false.

01:14

And at the end of the video, to prove science is in fact true,

01:16

I'll show you a car I built in 45 minutes based on what I learned,

01:19

and then show you how it did in competition.

01:21

So let's start with the fundamentals.

01:23

The Pinewood Derby is all about conservation of energy.

01:26

The amount of energy you start the race with is the same amount of energy you end the race with.

01:30

It's just a different kind.

01:30

So each of these blocks represents a unit of energy.

01:33

So at the beginning of the race, it's all potential energy, which is the energy associated with height.

01:39

So when you start, the higher your center of mass is on the track, the more of it you have.

01:43

And then at the end of the race, in a perfect world, all that potential energy has been converted to kinetic energy, block for block.

01:49

And kinetic energy is the energy of speed.

01:52

So you were really high on the track, and as you came down, all that height was converted into speed.

01:57

And you notice I said in a perfect world, because in reality, we lose some of that kinetic energy to friction.

02:03

It's dissipated through heat.

02:04

But you will notice that these two piles of friction and kinetic energy still add up to the original potential energy we started with.

02:11

Energy is conserved.

02:12

So if you can reduce friction, that means you're going to have more kinetic energy.

02:17

And that is the key.

02:18

This pile is the key to winning the race, because it has the speed term in there.

02:23

And whoever has the higher pile of blocks here, wins the race every time.

02:28

So for the rest of this video, we're going to discuss what truly matters in maximizing your kinetic energy, or your speed, or this pile.

02:35

How do you make this pile as big as possible with the least amount of effort?

02:39

Okay, so before we go any further, I want to introduce you to someone I met while doing the research for building the perfect pilot W car.

02:44

My name is Scott Acton, and I'm a physicist for Ball Aerospace.

02:48

About 10 years ago, my son and I kicked my wife's car out of the garage, and we converted it into the Pinewood Derby Research Facility.

02:55

For almost a year, we conducted experiments and used the laws of physics to determine exactly what it takes to make a winning Pinewood Derby race car.

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