- •Part I
- •Text. Physics and physical phenomena
- •Laboratory Exercises
- •Additional Material
- •M. V.Lomonosov
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Measurement of Volume
- •Text. The metric system
- •Dimensions of a Solid Body
- •Laboratory Exercises
- •Additional Material
- •Origin of the Metric System
- •Text. The kinetic theory and the three states of matter
- •3 Not to matter — не иметь значения will make full use — займут
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Mass and weight
- •3. Much, more, the most; little, less, the least; good, bet ter,
- •4, .,. Er than, more ... Than
- •5. At, on, over .., etc.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text, force, work, energy and power
- •Exercises
- •Additional Material
- •1. Have supported, has altered....
- •2. Energy can be converted...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Isaac Newton
- •Text. Heat
- •1. Heat is known to be a form of energy.
- •2. You place, you placed, you have placed. They take, they took, they have taken.
- •3. Newton began to think about heat.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Transmission of heat
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Good and Bad Conductors of Heat
- •Text. Calorimeters
- •1. It is usual to transfer ...
- •2. There is; is there; there is no ...
- •3. The setting up of ...; the reading of ...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Wave motion and sound
- •1. It does not move forward but returns again...
- •2. It is evident, it is clear.
- •Exercises
- •Additional Material
- •Text. Light
- •1. It becomes red-hot, it is the reason, it was cold...
- •2. High temperature produced by..., in a substance called... . Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Reflection and refraction of light
- •1. Do bodies emit? Does he make? Did it represent?
- •2. Have they shown? Had he travelled? Was it reflected? Is he going? Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Lenses
- •1. After leaving the lens...
- •Exercises
- •Additional Material
- •Text. Simple cell
- •1. The twitching of; the reading of...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Voltaic Cells
- •Text. The accumulator
- •1. A plate containing, a plate being immersed...
- •2. Achieved by connecting; determined by testing...
- •Exercises
- •Additional Material
- •Text. Principle of electric motor
- •1. They are used to pull...
- •2. When viewed, while doing...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Electric Bell Circuit
- •Text. Moving-coil ammeter and voltmeter
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Moving-Coil Galvanometer
- •Text. Electromotive force
Text. Wave motion and sound
Wave Motion. One of the most important phenomena in nature is the transmission of energy from one point to another by wave motion. This kind of motion is illustrated in many ways. When a stone is dropped into a pool of still water, the surface of the water is covered with circular wave-lets which widen out from the central point where the stone fell. The water does not really move outward from the central point, but it rises and then falls again. That is seen by observing a floating leaf or piece of wood. It does not move forward but returns again and again to its former positi-on. Hence, the water on which the leaf rests "must have this same kind of upward and downward motion rather than a forward motion.
When one end of a rope is fastened to a rigid wall and the free end moved up and down rapidly, each jerk travels along the rope, each portion of the rope communicating the jerk to the next portion. Each particle of the rope imparts its upward or downward motion to its neighbours. The jerk moves forward, but the particles of the rope move only up and down. Motions of this kind are wave motion. In all these cases it is evident that there is a vibrating centre which produces motions in those portions of the medium immediately in contact with it, and that these portions impart their motions to the neighbouring portions.
Transverse Waves. If part of a stretched string is drawn aside, the tension in the string tends to bring it back to its position of equilibrium. Since the string has inertia, the force that causes the displacement requires time to produce its full effect so that a wave can travel along the string with a definite velocity. Waves of this kind are easily produced in a rope fixed at one end and held in the hand at the other. If the rope is tightly stretched, a jerk imparted to the end of the rope travels down the rope as a wave. The more tightly the rope is stretched, the more rapidly the jerk travels down it. If a series of to-and-fro movements is imparted to the end of the rope a series of waves travels down the rope. Such waves are known as transverse waves, because the particles of the medium in which the waves travel are more perpendicular to the direction of the wave motion. They can be easily represented by plotting the displacements on the vertical axis and the distance from the source in a given direction on the horizontal axis. Light and other forms of electromagnetic waves are excellent illustrations of transverse waves.
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Listen and read words and word combinations to be remembered:
float [flout] плавать tension [tenjn] напряжение,
wavelet ['weivlit] небольшая волна натяжение
fast [a:sn] укреплять equilibrium [,ikwi'libriam]
jerk [djo:k] толчок равновесие
displacement [dis'pleis ment] velocity [vi'lositi] скорость
перемещение stretch [stretj] натягивать
impart [im'pa:t] сообщать,придавать travel ['traevl] распростра- transverse [traenz'vo:s] noперечный няться, перемещаться
widen ['waidn] расширяться, распро- axis ['aeksis] ось
страняться drop [drop] падать
represent [,repri'zent] представлять
wave motion волновое движение
upward and downward motion колебательное движение
vibrating centre центр колебания
to bring back зд. вернуться обратно
Give Russian equivalents to the following words without using a dictionary:
illustrate ['itestreit] motion ['moujan]
circular ['sae:kjula] vibrate [vai'breit]
central ['sentral] contact ['kontaekt]
portion ['po:jan] inertia [i'ne:rjja]
communicating [ka'mju:ni keiting]- effect [i'fekt]
forward ['fo:wad] series ['sieri:z]
perpendicular [,pe:pen'dikju1a] vertical ['ve:tikal]
source [so:s] horizontal [,hori'zontl]
electromagnetic [i'lektroumaeg’netik] illustration [,iles'treijen ]
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Models