TYPES OF MECHANICAL ENERGY
There are two types of mechanicalenergy - potentialenergy and kineticenergy. Supposea metal cylinderis lifted upand then released.It will fall. As it falls it can do a useful job. For example, it can drive a cuckooclock before it is released.
The cylinder has energy. It is called potential energy. Sometimes it is called gravitationalpotential energy, because the object is lifted through the Earth's gravitational field.
If water is pumpedfrom a large reservoirup to a small reservoir in the hills, it gainspotential energy. As the water runs down again to the lower reservoir, it drives a turbine.This turbine turns a generator and so produces electricity.
Some 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 motionenergy 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 brakesthe 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.
II. VOCABULARY
| 1. mechanical[mɪˈkænɪkəl] | механический |
| mechanical power | механическая энергия |
| 2. potential[pəˈtenʃəl] energy | потенциальная энергия |
| 3. kinetic[ki'netik]energy | кинетическая энергия |
| 4. to suppose[səˈpəuz] | полагать, предполагать |
| I suppose I got there about noon. | Я полагаю, что доберусь туда к полудню. |
| 5. cylinder[ˈsɪlɪndə] | цилиндр |
| 6. to lift up[lift] | поднимать |
| Suppose a metal cylinder is lifted up and then released. | Предположим, что металлический цилиндр поднимается и затем отпускается. |
| 7. to release[rɪˈli:s] | отпускать |
| 8. cuckoo['kuku:] | кукушка |
| cuckoo clock | часы с кукушкой |
| 9. gravitational[ˌɡrævɪˈteɪʃənəl] | гравитационный |
| 10. to pump[pʌmp] | закачивать, накачивать |
| The water for the house is pumpedup from a deep well. | Вода в дом подаётся насосом из глубокого колодца. |
| 11. reservoir[ˈrezəvwɑ:] | резервуар, бассейн, водохранилище |
| 12. to gain[ɡeɪn] | получать, приобретать |
| 13. turbine[ˈtɜːbaɪn] | турбина |
| 14. coiled[kɔɪld] | намотанный, свёрнутый в спираль |
| coiled spring [sprɪŋ] | пружина, рессора |
| 15. motion[ˈməuʃən] | движение |
| to put in motion | запустить, привести в движение |
| 16. to apply[əˈplaɪ] | применять, использовать |
| to apply brakes | тормозить |
| 17. to reduce[rɪˈdju:s] | понижать, сокращать |
| 18. to reduce prices | снижать цены |
III. READING COMPREHENSION
1. Answer the Questions
1. What many types of mechanical energy are there? What are they?
2. Why is potential energy sometimes called gravitational potential energy?
3. What energy does water gain if it is pumped from a large reservoir up to a small reservoir in the hills?
4. What do we call the energy of a moving car?
5. When energy is stored by a change in position - what is this energy called?
2. Read the statements and say whether they are true (T) or
false (F). Correct the false ones
1. There are two types of mechanical energy - potential energy and kinetic energy.
2. Sometimes gravitational potential energy is called kinetic energy.
3. The energy stored by the pumped water or the wound spring is kinetic energy.
4. If the object is lifted through the Earth's gravitational field this energy is called gravitational potential energy.
5. When a car is moving it has potential energy.
6. Petrol is burned in the engine and gives the car kinetic energy.
7. When the driver applies the brakes the car's kinetic energy is extended.
8. If a solid, liquid or gas is moving the substance has kinetic energy.
3. Choose the correct word or word combination
1. There are two types of .... energy - potential energy and kinetic energy.
a) solar
b) mechanical
c)gravitation
2. When a metal cylinder falls it can ... a cuckoo clock before it is released.
a) stop
b) lift
c) drive
3. Potential energy sometimes is called gravitational potential energy because the object is ... the Earth's gravitational field.
a) attracted to
b) released from
c) lifted through
4. If water is pumped from a large reservoir up to a small reservoir in the hills it gains ... energy.
a) potential
b) kinetic
c) solar
5. When energy is stored by a change in position it is called … energy.
a) potential
b) solar
c) mechanical
6. When the driver applies the brakes the car's kinetic energy is ...
a) applied
b) reduced
c) increased
4. Complete the sentences
1. There are two types of mechanical energy…………………………………………..
2. Potential energy is sometimes called gravitational potential energy because the
object is lifted through the Earth's……………………………………………………...
3. If water is pumped from a large reservoir up to a small reservoir in the hills it
gains………………………………………………………………………………….....
4. Some clocks, watches and toys operate from energy stored in……………………...
5. When energy is stored by a change in position it is called…………………………..
6. When a car is moving it has motion energy or………………………………………
7. When the driver applies the brakes the car's kinetic energy is………………………
8. If a solid, liquid or gas is moving, the substance has………………………………..
IV. ANALYZE
1. Match the words with their Russian equivalents
| 1 to reduce | aприменять, использовать |
| 2 motion | bбассейн, водохранилище |
| 3 mechanical | cполучать, приобретать |
| 4 to suppose | dдвижение |
| 5 to lift | eотпускать цилиндр |
| 6 to release a cylinder | fпружина, рессора |
| 7 spring | gмеханический |
| 8 to gain | hполагать, думать, предполагать |
| 9 reservoir | iподнимать |
| 10 to apply | jпонижать, сокращать |
2. Give the English equivalents
пружина, рессора ……………………………………………………………….…….
отпускать цилиндр…………………………………………………………………….
водохранилище………………………………………………………………………..
использовать…………………………………………………………………………..
сокращать ……………………………………………………………………………..
кинетический …………………………………………………………………………
механический …………………………………………………………………………
предполагать…………………………………………………………………………..
закачивать ……………………………………………………………………………..
пружина………………………………………………………………………………..
3. Put the words in the correct word order
1. energy / types / two / are / of / mechanical / there / .
2. coiled / toys / stored / from / spring / operate / in / a / some / energy / .
3. when / a / energy / is / motion / it / has / moving / car / .
4. patrol / is / engine / in / the / burned / and /kinetic / the /car / this / gives / energy /.
5. when / the / brakes / kinetic / the / reduced / the / car’s / applies / energy / is / driver / .
6. kinetic / a / substance / is / moving / the / liquid / has / if / energy / .
7. the / generator / turns / a / turbine / electricity / so / produces / and / .
4. Prove the following statements
1. There are two types of mechanical energy.
2. Sometimes potential energy is called gravitational potential energy.
3. When the driver applies the brakes the car's kinetic energy is reduced.
5. Match the words with their English definitions
| 1potential energy | athe action or process of moving or being moved |
| 2kinetic energy | bthink or assume that something is true or probable but lack proof or certain knowledge |
| 3reservoir | craise to a higher position or level |
| 4spring | dmake smaller or less in amount, degree, or size |
| 5gravitational | ebring or put into operation or use |
| 6motion | fthe energy that an object has as a result of moving |
| 7to apply | grelating to the force of gravity |
| 8to reduce | ha large natural or artificial lake used as a source of water supply |
| 9to lift | ia long thin piece of metal in the shape of a coil that quickly gets its original shape again after you stop stretching it |
| 10to suppose | jthe energy that a body or system has stored because of its position or condition |
V. TRANSLATE
1. Существует два типа механической энергии - потенциальная энергия и кинетическая энергия. …………………………...…………………………………...
2. Потенциальная энергия называется гравитационной потенциальной энергией, так как объект преодолевает гравитационное поле Земли. ………………………………………………………………………………………………………………………………
3. Если вода подается из большого резервуара в небольшой водоем в горах, она приобретает потенциальную энергию…………………………………………………………………………
4. Когда автомобиль движется, ему сообщается энергия движения или кинетическая энергия………………………………………………………..…
……………………………………………………………………………………
5. Бензин сгорает в двигателе и сообщает автомобилю кинетическую энергию…..……………………………………………………………………...
6. Когда водитель тормозит, кинетическая энергия автомобиля уменьшается.……………………………………………………………………
7. Если твердое тело, жидкость или газ движется, то это вещество обладает кинетической энергией. ……………………………………………
……………………………………………………………………………………
VI. SPEAK
1. Interview
Work in pairs and prepare an interview
Student Ais a going to make a report on types of mechanical energy
Student Ba physicist who knows mechanical energy.
2. Prepare a report on thetypes of mechanical energy