UNIT 22

 

I. Find out the words in the dictionary. Write them down and learn.

 

mutual, pervasive, to take for granted, measurement, product, to denote, adequate, weak, to apply to, relativity,  according to, curvature, rays of light, wave, indirect, to suffice

 

II. Read the text. Use a dictionary, if necessary.

 

Text: “Gravity”.

 

Gravity is a force of the mutual attraction between objects that have mass. Its influence in everyday life is so pervasive that it is taken for granted. The seventeenth-century mathematician and physicist Isaac Newton was the first to formulate the law of gravitation. He expressed it in mathematical terms that could be used in calculations. It was called Newton’s law of universal gravitation. It states that the gravitational force between two objects is directly proportional to the product of the masses of the two objects, and inversely proportional to the square of the distance between them.

To make calculations possible, it is necessary to include a constant, G, which is known as the universal constant of gravitation. Experimental measurements have shown that the gravitational constant G has a value of about 6.67 x 10^-11 m^-3 / (kg · s²).  

Physicists characterize the strength of a gravitational  field in  terms of the acceleration that a body of a certain mass and radius produces on a falling object. It can be found by equating the force of gravity between the body and a mass of 1kg with Newton’s second law of motion, which gives the acceleration produced by a force acting on a particular mass. The result (the acceleration due to gravity, or the gravitational field strength) is denoted by g, which for the Earth has a value of about 9.8 ms^-2.

Newton’s mathematical description of gravity is adequate for weak gravitational fields. But it fails when applied to large masses confined to small regions in which the force of gravity is very strong. In this case Einstein’s theory of gravitation (the General Theory of Relativity) has to be used.

According to Einstein’s General Theory of Relativity, the mutual attraction between objects is the result of the curving of space and time around them. The curvature has observable effects on rays of light that pass close to massive objects, such as the sun or other stars. Studies of these effects indicate that the idea of space-time curvature is valid. Einstein suggested that gravitation is a curved field in the space-time continuum, rather than a force as Sir Isaak Newton had thought.

One prediction of the General Theory is the existence of gravitational waves, a phenomenon produced whenever an object is accelerated. But gravitational waves are so weak that they have not yet been detected directly; at present there is only indirect evidence for their existence. In most situations, however, Newton's law suffices for calculating gravitational forces.

A commonplace manifestation of the gravitational attraction between massive bodies is the phenomenon of the tides, which results from the unequal attractions of the moon and sun on the water in the oceans of the earth. 

 

Note: 6.67x10^-11  - six point six seven multiplied by ten to the minus eleventh. 

 

III. Give adjectives corresponding to the following nouns and translate them.

 

Gravitation, attraction, mass, influence, calculation, universe, proportion, experiment, value, object, weakness, region, strength, theory, relativity, mutuality, validity, prediction, existence, evidence, inequality.

 

IV. Practice the following speech patterns.

 

Pattern 1.  Newton was the first to formulate the law of gravitation.

 

Einstein – the General Theory of Relativity

Einstein – the idea of space-time curvature

Newton – the laws of motion

 

Pattern 2.  Newton’s theory is adequate for weak gravitational fields.

 

Einstein’s theory – strong gravitational fields

Newton’s theory – the motion of planets

 

V. Find the sentences that can’t be found in the text.

 

1. Gravity is a force of the mutual attraction between objects that have mass.
2. Physicists characterize the strength of a gravitational field in terms of acceleration.
3. Newton’s mathematical description of gravity is adequate for weak gravitational fields.
4. According to Einstein’s General Theory of Relativity, the mutual attraction between objects is the result of the curving of space and time around them.
5. One prediction of the General Theory is the existence of gravitational waves.
6. In classical Newton physics, the gravitational attraction between two object of masses M and m is proportional to the product of their masses and inversely proportional to the square of the distance between their centers of mass.
7. In relativistic Einsteinian physics, however, massive object, such as stars, deform space, forming a “gravity well”.
8. In most situations Newton’s law suffices for calculating gravitational forces.

 

VI. Find English equivalents in the text:

 

1. принимается за аксиому _____________________________________
2. может использоваться при вычислениях ______________________
3. закон всемирного тяготения гласит __________________________
4. квадрат расстояния между _____________________________________
5. напряженность гравитационного поля ___________________________
6. ограниченный малыми размерами ______________________________
7. искривление пространства и времени ___________________________
8. оказывает воздействие на лучи света, которое можно наблюдать ____
9. проходить близко ____________________________________________
10. одна из гипотез Общей Теории Относительности __________________
11. существование гравитационных волн ____________________________
12. есть только косвенное свидетельство существования _______________
13. гравитационное притяжение ____________________________________
14. приливы _____________________________________________________
15. проявление __________________________________________________

 

VII. Find Russian equivalents to the following words and expressions in the text.

 

1. mutual attraction _____________________________________________
2. its influence is taken for granted _________________________________
3. was the first to formulate _______________________________________
4. to express in mathematical terms _________________________________
5. the law of universal gravitation ___________________________________
6. is directly proportional __________________________________________
7. is inversely proportional _________________________________________
8. experimental measurements ______________________________________
9. it can be found by equating ______________________________________
10. when applied to large masses ____________________________________
11. is adequate for weak gravitational fields ____________________________
12. in terms of acceleration _________________________________________
13. is denoted by “g” ______________________________________________
14.  the result of the curving ________________________________________
15. the idea is valid _______________________________________________
16. have not been detected directly __________________________________
17. Newton’s law suffices __________________________________________

 

VIII. Analyze the structure of the sentences. 

 

1. It can be found by equating the force of gravity between the body and the mass of 1 kg. with Newton’s second law of motion, which gives the acceleration produced by a force acting on a particular mass.
2. It [the law] fails when applied to large masses confined to small regions in which the force of gravity is very strong. 

 

IX. Fill in the missing words:

 

1. Gravity is a force of the _______ attraction between objects that have mass.
2. Its influence in everyday life is so pervasive that it is taken ___ _______.
3. The law of universal gravitation states that the gravitational force between two objects is _____ ______ to the product of the masses of the two objects.
4. Physicists characterize the ______ of a gravitational field in terms of  ________.
5. It can be found by ______ the force of gravity between the body and a mass of 1kg with Newton’s second law of motion.
6. Newton’s mathematical description of gravity is _______ for _______ gravitational fields.
7. Accordingly to Einstein’s General Theory of Relativity, the ______ attraction between objects is the result of the _______ of _______ and time around them.
8. One prediction of the General Theory is the _______ of gravitational waves.
9. In most situations, however, Newton’s law _______ for calculating gravitational forces.
10. A commonplace _______ of the gravitational attraction between massive bodies is the phenomenon of the tides.

 

X. Fill in the necessary prepositions.

 

1. Gravity is a force ___ the mutual attraction ___ objects that have mass.
2. The law states that the gravitational force ___ two objects is directly prepositional ___ the product ___ the masses ___ the two objects.
3. The second law ___ motion gives the acceleration produced ___ a force acting ___ a particular mass.
4. Newton’s description ___ gravity is adequate ___ weak gravitational fields.
5. But it fails when applied ___ large masses confined ___ small regions.
6. ___ present there is only indirect evidence ___ their existence.
7. ___ most situations, however, Newton’s law suffices ___ calculating gravitational forces.
8. The phenomenon ___ the tides results ___ the unequal attraction ___ the moon and sun ___ the water ___ the oceans ___ the earth.

 

XI. Practice with someone asking and answering.

 

1. What is gravity?
2. Why is it taken for granted?
3. Who was the first to formulate the law of gravitation?
4. How was it called?
5. What does it state?
6. In what way do physicists characterize the strength of a gravitational field?
7. How can the strength be found?
8. Is Newton’s mathematical description of gravity adequate for all gravitational fields?
9. When does it fail?
10. What theory has to be used in this case?
11. What is the essence of Einstein’s General Theory of Relativity?
12. What is gravitation according to Einstein?
13.  What is one of the predictions of the General Theory?
14. Have gravitational waves been detected?
15. What law suffices for calculating gravitational forces in most situations?

 

XII. Dictation-translation.

 

1. Гравитация – это сила взаимного притяжения между телами, которые обладают массой.
2. Математик и физик семнадцатого века Исаак Ньютон первым сформулировал Закон всемирного тяготения.
3. Закон гласит, что сила гравитации между двумя телами прямо пропорциональна произведению масс двух тел и обратно пропорциональна квадрату расстояния между ними.
4. Физики характеризуют напряженность гравитационного поля с помощью понятия ускорения.
5. Математическое описание гравитации Ньютона подходит для слабых гравитационных полей.
6. В соответствии с Общей Теорией Относительности, взаимное притяжение между телами является результатом искривления пространства и времени вокруг них.