8. Transform the sentences using Passive Voice where it is possible:

Suppose that we place a body on a shelf. It has the capacity to perform work. If we attach this body to another one of equal weight and allow it to fall freely, the body will descend to the ground and its rate will steadily increase. In doing so, it will lift the other body up to the level of the shelf. When the falling body reaches the ground, the process of converting potential energy into kinetic energy evidently comes to an end.

Text 2 b Energy

Give a summary of the text.

Man’s entire life is linked with energy. We need more energy with each passing year. Energy was, is and will remain the foundation of economy, of the development of civilization. That’s why energy problems are now among the most important problems that cause concern of the whole of mankind.

What is energy? What are its forms and sources? How is mankind’s ever growing need for energy to be satisfied?

The capacity for doing work is called energy. A body possesses energy when due to its position or condition it is capable of doing work, and the work it can do is a measure of its energy.

As we know, energy is of two types: potential or kinetic. Potential energy is the energy that has been stored by a body within it. A body possesses potential energy thanks to its position or condition. All fuels (coal, oil, gas, etc.) contain chemical potential energy because they produce the heat that will bring to motion modern engines and do physical work of great importance for our modern industrial world.

Water in a dam is a good example of potential (stored up) energy as well. It possesses this energy because of its higher position. When water is falling with great speed it turns huge turbine wheels and supplies them with kinetic energy. The motion of the turbine can now produce electric energy, which will be transmitted to distant homes and factories. Here electric devices are serving man in a thousand of ways.

Thus, kinetic energy is the energy that a body has due to motion. The potential energy of the weight in its highest position is the same as its kinetic energy after it has fallen under the action of gravity to its lowest position. It may be very large, as the motion of the earth, or very small as that of molecules or even electrified particles.

Unit 3 Grammar:

1. Present Participle.

2. Continuous Tenses (Active, Passive).

Reading Exercises

1. Practice reading the following one-syllable words:

few, force, work, push, pull, change, rest, case, weight, lie, ground, stone, done, sense, word, hold, true, through, mean, kind, fall, store, flow, use, wheel, coal, thrown, heat, burn.

2. Practice reading the following two-syllable words with the stress on the first syllable:

equal, product, body, order, over, meaning, language, distance, turbine, differ, factor.

3. Practice reading the following two-syllable words with the stress on the second syllable:

among, connect, apply, perform, effect, possess, begin, refer, demand, belong, result, produce, account, amount, divide, require.

4. Practice reading many-syllable words:

Chemical, definite, different, determine, multiply, operate, ability, energy, mechanical, physical, calculate, multiply, electrical, everyday, scientific.

5. Practice reading the following word-combinations:

Taken into account, for example, in order to, in fact, in the language of science, in everyday life, connected with the idea of time, a state of rest, a state of motion, from motion to rest, in scientific sense of the word, the force is applied, to result in no work, the amount of performed work, the product of the force by the distance, the ability to work, different kinds of energy, all moving bodies, to drive the waterwheels of turbines.