- •Міністерство освіти і науки України
- •Lesson 1
- •Дієслово to be в Indefinite Active
- •Notes to the Text
- •British Universities
- •Vocabulary notes
- •Lutsk National Technical University
- •Key dates in science
- •Lesson 2
- •Ступені порівняння прикметників
- •Vocabulary notes
- •Sсience and Technological Progress in Modern Society
- •Notes to the Text
- •Text 2b Massachusetts Institute of Technology
- •Notes to the Text
- •Vocabulary notes
- •I am a Student
- •Key dates in science
- •Lesson 3
- •Відмінювання стандартного дієслова to work у Past Indefinite
- •Відмінювання нестандартного дієслова to write у Past Indefinite
- •Vocabulary notes
- •Is there an End of the Computer Race?
- •Notes to the Text
- •From the history of computer.
- •Vocabulary notes
- •English Language
- •Key dates in science
- •Lesson 4
- •Відмінювання дієслова to tell в часах групи Indefinite Passive
- •Vocabulary notes
- •The Internet
- •Notes to the Text
- •Programming Languages
- •Notes to the text
- •Vocabulary notes
- •Music, Television, and Video Games as a Way of Spending Leisure Time
- •Key dates in science
- •Lesson 5
- •Відмінювання дієслова to work у Present Continuous Active
- •Відмінювання дієслова to work у Future Continuous Active
- •Vocabulary notes
- •Vocabulary notes
- •Vocabulary notes
- •Environmental Protection in Ukraine
- •Key dates in science.
- •Lesson 6 Grammar. Часи групи Continuous Passive
- •Відмінювання дієслова to tell в часах групи Continuous Passive
- •Vocabulary notes
- •Notes to the text
- •Yuri Kondratyuk and the Moon
- •Notes to the Text
- •Vocabulary notes
- •Science in Ukraine
- •Key dates in science
- •Lesson 7
- •Відмінювання дієслова to write у часах групи Perfect Active
- •Vocabulary notes
- •Electricity
- •Notes to the Text.
- •Notes to the text
- •Vocabulary notes
- •The youth of America.
- •Key dates in science
- •Lesson 8
- •Відмінювання дієслова to tell в часах групи Perfect Passive
- •Vocabulary notes
- •Changes in Matter
- •The Science of Ice
- •Notes to the Text
- •Vocabulary notes
- •The Engineering Profession
- •Key dates in science
- •Lesson 9
- •Узгодження часів
- •Vocabulary notes
- •Television
- •Notes to the Text
- •Telegraph
- •Vocabulary notes
- •1. Mass media засоби масової інформації
- •Mass Media
- •Key dates in science.
- •Lesson 10.
- •Форми модальних дієслів
- •Еквіваленти модальних дієслів
- •Vocabulary notes
- •Made in Space
- •Notes to the text
- •Vocabulary notes
- •Vocabulary notes
- •Ukraine’s Economy
- •Key dates in science
- •Lesson 11
- •Форми дієприкметника теперішнього часу
- •Vocabulary notes
- •Transport for Tomorrow.
- •Notes to the Text
- •Text 11b How It Works.
- •Notes to the text
- •Vocabulary notes
- •Key dates in science
- •Lesson 12
- •Утворення форми дієприкметника минулого часу
- •Vocabulary notes
- •Time Travel and New Universes
- •Notes to the Text
- •The Role of Gravity
- •Notes to the text
- •Vocabulary notes
- •Lesson 13
- •Форми інфінітиву
- •Vocabulary notes
- •Notes to the Text
- •Text 13b Optical Technology
- •Notes to the text
- •Vocabulary notes
- •Developing the Telecommunications
- •Notes to the Text
- •Key dates in science.
- •Lesson 14
- •Форми герундія
- •Vocabulary notes
- •A New Era for Aircraft
- •Notes to the text
- •Vocabulary notes
- •Vocabulary notes
- •The Economy of the usa
- •Key dates in science
- •Lesson 15.
- •Об’єктний інфінітивний комплекс
- •Суб’єктний інфінітивний комплекс
- •Vocabulary notes
- •Notes to the Text
- •Notes to the text
- •Vocabulary notes
- •Industry of Great Britain
- •Key dates in science
- •Vocabulary notes
- •Descending to New Ocean Depths
- •Notes to the Text
- •Types of Submersible
- •Notes to the Text
- •Vocabulary notes
- •Money in the Modern World
- •Key dates in science
- •Префіксів та суфіксів
- •Lesson 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
- •43018 Луцьк, вул. Львівська, 75
The Role of Gravity
Among the fundamental forces of nature, gravity is of special interest for several reasons. It is, first of all, the only truly universal force. It acts on every material thing from electron to galaxy, and, as we have learned in this century, it even acts on the particles like protons and neutrinos or energy in any form. Second, gravity has played a uniquely important role in the development and growth of mechanics. Newton, in his definite formulation of mechanics, drew upon studies of motion near the earth, influenced by local gravity, and of planetary motion far from the Earth, influenced by the sun’s gravity.
Since Newton’s time, motion governed by gravitational force has provided the strictest tests of mechanics, has served as stimulus for much of the mathematical elaboration of the theory of mechanics, has led to the discovery of distant new planets, and, in our own era of artificial satellites, and has revealed new details of the shape and structure of the earth; though the study of the orbit of Mercury became the first hint of an imperfection of Newtonian mechanics. Mercury’s refusal to follow precisely the laws of classical mechanics stands as one of the experimental supports of the new mechanics of Einstein’s general relativity.
Finally, gravity has a special place in mechanics because of its essential link with motion. Most forces on Earth can be measured with a spring balance or other device that involves no motion. The same is obviously not true of the forces acting on the planets. These can be determined only if we study the motion of the planets. The motion determines the force, but at the same time the force determines the motion. Planetary mechanics must be a self-consistent theory in which the law of motion (Newton’s second law) and the law of gravitational force are intertwined.
Gravity affects everything. From our bodies to the mechanism we use to build cars and buildings, to the flames we use to heat our homes, our world is controlled by gravity. Even flames burn differently without gravity. Reduced gravity reduces convection currents, the currents that cause warm air or fluid to rise and cool air or fluid to descend on Earth. This absence of convection changes the flame shape in orbit and allows studies of the combustion process that are impossible on Earth. The absence of convection allows molten metals or other materials to be mixed more thoroughly in orbit than on Earth, opening the way to a whole new world of composite materials. Scientists plan to study this field, to create better metal alloys and more perfect materials for applications such as computer chips. Investigations that use lasers to cool atoms to near absolute zero may help us understand gravity itself.
While investigating our surrounding, we have been limited, until recently, to accepting gravity as a given factor in all our studies. History shows that changing what once was constant can lead to revolutionary discoveries.