Английский - 2курс_3семестр_physics

CWhat is wrong with the following statement? ―A comet in an elliptical orbit speeds up as it approaches the sun, because the sun‘s force on it is increasing.‖

DWhy would it not make sense to expect the earth‘s gravitational force on a

bowling ball to be inversely proportional to the square of the distance between

their surfaces rather than their centers?

EDoes the earth accelerate as a result of the moon‘s gravitational force on it? Suppose two planets were bound to each other gravitationally the way the earth and moon are, but the two planets had equal masses. What would their motion be like?

FSpacecraft normally operate by firing their engines only for a few minutes at a time, and an interplanetary probe will spend months or years on its way to its destination without thrust. Suppose a spacecraft is in a circular orbit around Mars, and it then briefly fires its engines in reverse, causing a sudden decrease in speed. What will this do to its orbit? What about a forward thrust?

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GRAMMAR

The Gerund (the –ing form)

The “-ing form” is the verb form with the –ing suffix.

Sam likes fishing.

We use the “the –ing form”:

 as a noun.

Walking is a good form of exercise.

 usually after the verbs like, love, dislike, hate, enjoy, prefer.

Helen likes watching old films on TV.

 after the verbs start, begin, stop, finish.

He started writing his composition an hour ago.

 after prepositions.

I‘m tired of going to work by bus every morning.

 after the verb go when we talk about activities.

We usually go skiing at the weekends.

 after the expressions be busy, it’s no use, it’s no good, it’s (not) worth, what’s the use of …?, there is no point in.

Father is busy repairing the car.

 after verbs such as avoid, admit, confess, deny, look forward to, mind, regret, risk, spend, suggest, etc.

Tony avoided answering my question.

NOTE:

1. We can use the –ing form or the to-infinitive after the verbs start, begin, continue, like, love, prefer and hate. e.g. He started writing/to write his speech last night.

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2.We use the to-infinitive and not the –ing form after the expressions would love/would like/would prefer. e.g. I would love to have my own house one day. (NOT: I would love having my own house one day.)

3.We can use the bare infinitive or the –ing form after the verbs see, hear, feel and watch. Note the difference in meaning, however.

a)I saw Peter cross the street. (I saw the whole action – by the time I left, Peter was on the other side of the street.)

b)I saw Peter crossing the street. (I only saw part of the action – I don‘t know if

Peter got to the other side of the street by the time I left.)

EXERCISES

1. Put the verbs in brackets into the correct infinitive form or the –ing form.

1)I would like …to go… (go) out tonight.

2)He hates … (play) cards.

3)She is too excited … (sleep).

4)You must … (get up) early in the morning.

5)I regret … (spend) so much money last weekend.

6)They go … (run) every Tuesday evening.

7)I saw Helen … (wash) the dishes. It took her only ten minutes.

8)I started … (learn) French two years ago.

9)He was very pleased … (see) her again.

10)The dentist advised him … (stop) eating sweets.

2. Put the verbs in brackets into the correct infinitive form or the –ing form.

Last weekend, Toby‘s parents let him (1) …go… (go) to the funfair with his friends. When they arrived, they didn‘t know which ride (2) … (try) first, but someone suggested (3) … (start) with the ghost train. Everyone agreed that this was a very good idea. After they had finished (4) … (ride) the ghost train, they

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moved on to the other rides. Toby admitted (5) … (be) afraid on the fast rollercoaster, but he was still happy enough (6) … (go) on it three times! He and his friends wanted (7) … (try) all of the rides but they were too exhausted (8) … (do) everything in one day. Toby suggested (9) … (come) back the following weekend. Then, they all decided (10) … (go) home. They all loved (11) … (visit) the funfair and they are looking forward to (12) … (return) this weekend.

3. Complete each sentence with two to five words including the word in bold.

1) Alec is too short to be a basketball player.

tall Alec isn‘t …tall enough to be… a basketball player. 2) Exercising regularly is good for you.

exercise It is good … regularly.

3) Mary was so late that she didn‘t catch the bus. too Mary was … the bus.

4) This book is too boring for me to read. enough This book isn‘t … read.

4. Correct the mistakes.

1)I‘m not too tall to reach the top cupboard.

2)He is enough fast to win the race.

3)I‘m old enough travelling alone.

4)You must to get up now.

5)She suggested to go to the cinema on Friday night.

6)He promised sending me a postcard.

7)It‘s no use to try to change her mind.

8)She knocked before to open the door.

9)He is tired enough to come to the party.

10)I am poor enough to buy a new sports car.

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UNIT 11

Evidence for Repulsive Gravity

Read the text and be ready to answer teacher’s questions.

Until recently, physicists thought they understood gravity fairly well. Einstein had modified Newton‘s theory, but certain characteristics of gravitational forces were firmly established. For one thing, they were always attractive. If gravity always attracts, then it is logical to ask why the universe doesn‘t collapse. Newton had answered this question by saying that if the universe was infinite in all directions, then it would have no geometric center toward which it would collapse; the forces on any particular star or planet exerted by distant parts of the universe would tend to cancel out by symmetry. More careful calculations, however, show that Newton‘s universe would have a tendency to collapse on smaller scales: any part of the universe that happened to be slightly more dense than average would contract further, and this contraction would result in stronger gravitational forces, which would cause even more rapid contraction, and so on.

When Einstein overhauled gravity, the same problem reared its ugly head. Like Newton, Einstein was predisposed to believe in a universe that was static, so he added a special repulsive term to his equations, intended to prevent a collapse. This term was not associated with any attraction of mass for mass, but represented merely an overall tendency for space itself to expand unless restrained by the matter that inhabited it. It turns out that Einstein‘s solution, like Newton‘s, is unstable. Furthermore, it was soon discovered observationally that the universe was expanding, and this was interpreted by creating the Big Bang model, in which the universe‘s current expansion is the aftermath of a fantastically hot explosion. An expanding universe, unlike a static one, was

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capable of being explained with Einstein‘s equations, without any repulsion term. The universe‘s expansion would simply slow down over time due to the attractive gravitational forces. After these developments, Einstein said woefully that adding the repulsive term, known as the cosmological constant, had been the greatest blunder of his life.

This was the state of things until 1999, when evidence began to turn up that the universe‘s expansion has been speeding up rather than slowing down! The first evidence came from using a telescope as a sort of time machine: light from a distant galaxy may have taken billions of years to reach us, so we are seeing it as it was far in the past. Looking back in time, astronomers saw the universe expanding at speeds that were lower, rather than higher. At first they were mortified, since this was exactly the opposite of what had been expected. The statistical quality of the data was also not good enough to constitute ironclad proof, and there were worries about systematic errors. The case for an accelerating expansion has however been nailed down by high-precision mapping of the dim, sky-wide afterglow of the Big Bang, known as the cosmic microwave background. Some theorists have proposed reviving Einstein‘s cosmological constant to account for the acceleration, while others believe it is evidence for a mysterious form of matter which exhibits gravitational repulsion. The generic term for this unknown stuff is ―dark energy.‖

As of 2008, most of the remaining doubt about the repulsive effect has been dispelled. During the past decade or so, astronomers consider themselves to have entered a new era of high-precision cosmology. The cosmic microwave background measurements, for example, have measured the age of the universe to be 13.7±0.2 billion years, a figure that could previously be stated only as a fuzzy range from 10 to 20 billion. We know that only 4% of the universe is atoms, with another 23% consisting of unknown subatomic particles, and 73%

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of dark energy. It‘s more than a little ironic to know about so many things with such high precision, and yet to know virtually nothing about their nature. For instance, we know that precisely 96% of the universe is something other than atoms, but we know precisely nothing about what that something is.

The WMAP probe’s map of the cosmic microwave background is like a

“baby picture” of the universe.

Put 10 questions to the text.

Write a short summary.

What do you know about the Big Bang? Share the information with other students.

Topics for discussion.

1)Einstein‘s understanding of gravity.

2)The Big Bang model.

3)The dark energy.

4)The new era of cosmology.

5)Scientists who worked at ―gravity‖.

Try to explain the following words in your own words.

gravity, theory, particle, expansion, measurement, collapse, cosmology, nature

Write out unknown words from the text and make up sentences using these words.

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GRAMMAR

The Participles

The participles are:

a)present participles (playing, running, etc.),

b)past participles (played, written, etc.) and

c)perfect participles (having written, etc.)

Present and past participles can be used as adjectives.

The present participle (-ing) describes what somebody or something is (it answers the question „What kind?‟). The past participle (-ed) describes how somebody feels (it answers the question „How do you feel?‟).

It‘s a very tiring job. (What kind of job? Tiring.)

He‘s very tired. (How does he feel? Tired.)

Participles can also be used:

 to express time.

After doing/having done her homework, she watched TV.

Having done her homework, she watched TV.

(= After she had done her homework, she watched TV.) He broke his arm (while) playing hockey.

(= He broke his arm while he was playing hockey.)

 to express reason. Being late, Adam took a taxi.

(= Because he was late, Adam took a taxi.)

Having spent all her money, Pam asked for a loan.

(= Because she had spent all her money, Pam asked for a loan.)

 instead of a relative pronoun and full verb.

The man standing at the door is my boss.

(= The man who is standing at the door is my boss.)

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The information presented in the article was invaluable.

(= The information which was presented in the article was invaluable.)

instead of the past indefinite in narratives when we describe actions happening immediately one after the other.

Seeing the shadow, he screamed.

(= He saw the shadow and he screamed.)

 to avoid repeating the past continuous in the same sentence.

She was climbing up a ladder carrying a bucket.

(= She was climbing up a ladder and she was carrying a bucket.)

EXERCISE

1. Rewrite the sentences using participles.

1) He was lying on the bed and he was reading a book.

…He was lying on the bed reading a book….

2)Lisa took a deep breath and dived into the water.

3)Jack burnt his finger while he was lighting a fire.

4)After Ann had ironed the clothes, she put them away.

5)Because he was cold, James turned on the heater.

6)The photographs, which were taken at the reception, were blurred.

7)Alison washed the paintbrushes before she painted the living room.

8)She was sitting on the sofa and she was knitting a jumper.

9)The girl who is sitting next to Alison is Vicky.

10)Because he had forgotten to do the shopping, he ate out that night.

11)Emma turned the key in the lock and opened the door.

2. Underline the correct participle.

On Saturday, I took my children to the circus. I thought I would have a 1) boring/bored time, but actually I was quite 2) astonishing/astonished by the 3) amazing/amazed acts. We were 4) stunning/stunned by the acrobats. They

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balanced on top of each other with incredible ease. We were really 5) impressing/impressed by their performance. The children found the liontamer‘s act 6) exciting/excited. I felt 7) terrifying/terrified when he put his hands into the lion‘s mouth, but the children were 8) amusing/amused and they clapped loudly. A magician performed many incredible tricks; it was 9) fascinating/fascinated to watch him make various objects disappear and reappear. The children were more 10) interesting/interested in the elephant act. When the huge animals came into the arena, the audience cheered. The elephants were well-trained and their tricks were 11) entertaining/entertained.

Some children from the audience were invited to ride on the elephants‘ backs.

My children were 12) disappointing/disappointed when they were not chosen, but their disappointment faded when the clowns took the centre ring. It was quite a 13) captivating/captivated show. By the time we got home we all felt 14) exhausting/exhausted.

3. Choose from the brackets necessary form of the participle.

1)The girl (writing, written) on the blackboard is our best student. Everything (writing, written) here is quite right.

2)The house (surrounding, surrounded) by tall trees is very beautiful. The wall (surrounding, surrounded) the house was very high.

3)Who is that boy (doing, done) his homework at that table? The exercises (doing, done) by the students were easy.

4)We couldn‘t see the sun (covering, covered) by dark clouds.

5)Name some places (visiting, visited) by you last year.

6)I picked up the pencil (lying, lain) on the floor.

7)Yesterday we were at the conference (organizing, organized) by the students.

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