Pulling Strings to Build Pyramids

READING PASSAGE

1

You should spend about 20 minutes on Questions 1-13, which are based on Reading

Passage 1 below.

Pulling Strings to Build Pyramids

No

one knows exactly how the pyramids were built.

Marcus

Chown reckons

the answer could be 'hanging in the air'.

The pyramids of Egypt were built more than three thousand years ago, and no

one knows how.

The conventional picture is that tens of thousands of slaves

dragged stones on sledges

（

第

1

题答案）

. But there is no evidence to back thisup.

Now

a

Californian

software

consultant

called

Maureen

Clemmons

has

suggested that kites might have been involved. While perusing a book on the

monuments

of

Egypt,

she

noticed

a

hieroglyphthat

showed

a

row

of

men

standing in odd postures

（第

2

题答案）

.They were holding what looked like ropes

that

led,

viasome

kind

of

mechanical

system,

to

a

giant

bird

in

the

sky.

She

wondered if perhaps the bird was actually a giant kite, and the men were using

it to lift a heavy object.

Intrigued, Clemmons contacted Morteza Gharib, aeronautics professor at the

California Institute of Technology. He was fascinated by the idea. 'Coming from

Iran, I have a keen interest in Middle Eastern science,' he says. He

too

was

puzzled by the picture that had sparked Clemmons's interest. The object in the

sky

apparently

had

wings

far

too

short

and

wide

for

a

bird.

‘The

possibility

certainly existed that it was a kite,' he says. And since he needed a summer

project for his student Emilio Graff, investigating the possibility of using kites as

heavy lifters seemed like a good idea.

Gharib and Graff set themselves the task of raising a 4.5-metre stone column

圆柱

from

horizontal

水平的

to

vertical,

using

no

source

of

energy

except

the

wind.

（

第

4

题

答

案

）

Their

initia

calculations

and

scale-model

wind-tunnel

experiments

convinced

them

they

wouldn't

need

a

strong

wind

to

lift

the

33.5-tonne column. Even a modest force, if sustained

,

over a long time, would

do.

（第

5

题答案）

The key was to use a pulleysystem that would magnify the

applied force. So they rigged up a tent-shaped scaffolddirectly above the tipof

the

horizontal

column, with

pulleys

suspended

from the

scaffold's

apex.

The

idea was that as one end of the column rose, the base would roll across the

ground on a trolley.

Earlier this year, the team put Clemmons's unlikely theory to the test, using a

40-squaremetre

rectangular

nylonsail.

The

kite

lifted

the

column clean

off

the

ground. 'We were absolutely stunned,' Gharib says. 'The instant the sail opened

into the

wind, a huge force

was generated and the column was raised to the

vertical in a mere 40 seconds.