V. Translate
1 . Каждый день солнце излучает огромное количество
энергии………………………………………………..…….….
……………………………………………………………….….
2.Солнечная энергия является самой распространенной энергией………………………………………………………...
……………………………………………………………………………..…….
3. Люди использовали солнце для сушки одежды и пищи в течение тысячелетий
…………………………………………………………………………………….……
4. Солнце находится в 150 миллионах километров от Земли и является удивительно мощным источником энергии…………………………...…………….
………………………………………………………………………………………….
5. Солнце – это полезный, дешевый и надежный источник энергии……………...
………………………………………………………………………………………….
6. Солнечная энергия является бесплатной – она не требует топлива, не
производит отходов и не загрязняет окружающую среду………………………….
………………………………………………………………………………………….
7. Благодаря солнечной энергии мы можем управлять технологиями и
различными машинами без использования топлива………………………………..
……………………………………………………………………………………….…
8. Строительство солнечных электростанций является очень дорогостоящим
………………………………………………………………………………………….
VI. Speak
1. Interview
Work in pairs and prepare an interview
Student A is a newspaper reporter.
Student B is against using solar energy.
2. Prepare a report on the advantages and disadvantages of solar energy
U
NIT
6
MECHANICAL ENERGY
Preview
Answer the questions. Then talk about your answers.
1) What energy is associated with the motion and position of an object?
2) Can you give examples of mechanical energy?
3) Where does mechanical energy come from? |
I. Listening and reading
Listen to the text
Read and translate the text
Types of mechanical energy
T
here
are two types of mechanical
energy
-
potential
energy
and kinetic
energy.
Suppose
a
metal cylinder
is
lifted
up and
then released.
It
will fall. As it falls it can do a useful job. For example, it can
drive a cuckoo
clock
before it is released.
The cylinder has energy. It is called potential energy. Sometimes it is called gravitational potential energy, because the object is lifted through the Earth's gravitational field.
If water is pumped from a large reservoir up to a small reservoir in the hills, it gains potential energy. As the water runs down again to the lower reservoir, it drives a turbine. This turbine turns a generator and so produces electricity.
S
ome
clocks, watches and toys operate from energy stored in a
coiled spring. When
energy is stored by a change in position, it is called potential
energy. The
energy
stored by the pumped water or the wound spring is potential energy.
When a car is moving it has motion energy or kinetic energy. Petrol is burned in the engine and gives the car this kinetic energy. It is difficult to make this energy do any other useful job. When the driver applies the brakes the car's kinetic energy is reduced. The brakes then become warm and the air around them is heated. The energy is wasted or "lost".
If a solid, liquid or gas is moving the substance has kinetic energy.