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Ускорение, с которым движется М.Т. массой m=2 кг, определяется соотношением a=1+2t. Чему равна величина силы, действующая на М.Т. в момент времени t=2c.
F=? H-
Предмет:
Физика -
Автор:
tough guy27q5 - 6 лет назад
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Ответы 1
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1) находим ускорение a(2)=1+2*2=5 м/с22) по второму закону НьютонаF=m*a=2*5=10 Н
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Автор:
lianapkuc - 6 лет назад
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Translate the text into Russian.
There is a good proverb that I like very much: “We eat to live, but do not live to eat.” I think this is true because food is something that we need to stay alive. Food is a source of energy. Nevertheless I like eating tasty food even though I am not much into it. So, for some people food is a source of pleasure, too. But the food that we eat should also be healthy.
I eat similar food every day. It is usually very simple. My daily meal consists of light breakfast, lunch (at school), dinner and supper.
In the morning I usually have some tea with cheeseburgers or hamburgers, some porridge or cottage cheese with sugar or jam.
I like tea with toast and home-made jam. I have a sweet tooth, so I like chocolate and different cakes, sweets very much.
I usually have lunch at school – it’s juice or tea and sandwiches that I take from home. I can also go to a canteen.
For dinner when I come home I have vegetable soup. Actually I don’t like soup. But I have to eat it because it’s healthy. But when I come to my granny I can’t stop trying her specialty - borsch or shi. Soup with meat balls that my mom cooks is my favourite. I can also have a salad or fried fish. I usually do not have desserts. Maybe some green or black tea with lemon.
For supper we usually have different kinds of potato dishes or pasta. I like meat very much. But I also like fish and other sea products – shrimps, squids, salmon and mackerel.
Vegetables are also what I love! Different vegetables are always on our dinner table. My mom makes tasty salads. I love different salads with dressings. I don’t eat much mayonnaise. Our salads usually have olive oil or sour cream as a dressing. We buy different fruits as well. My favourite fruits are bananas and tangerines.
I also love all kinds of dairy products like milk, yoghurt, kefir, cottage cheese and cheese.
While eating I usually drink juice or tea.
I think fast food (like McDonalds) is very bad for our health. Ready-made food like pelmeni, hamburgers and so on is also not very good. So, we try to cook at home. It is better to spend some time cooking, than to have health problems.
Well, of course, my family likes to try new dishes. So my mom always invents a new salad or cooks a new an interesting recipe if she has time on weekends.
I try not to eat just before I go to bed.
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замінити букви цифрами , щоб рівність була істиною КО+ЛО=БОК різні букви-різні цифри
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1. substation
2. grid
3. transformer
4. induction
5. resistance a) the production of electricity in one object by another which already has electrical (or magnetic) power.
b) a network of electricity supply wires connecting power stations.
c) a place where electricity is passed on from a generating station into the general system.
d) the power of a substance to resist the passing through it of an electric current.
e) an apparatus for changing electrical force, usually from one voltage to another.
Exercise 8. Read the text and ask five questions on it.
phasor diagram – векторная диаграмма
armature – якорь (электрической машины)
excitation – возбуждение; намагничивание
heat rate – удельный расход топлива
curve – кривая (диаграмма)
incremental – увеличивающийся постепенно
dispatch – распределение
to allocate – распределять; размещать
emission – выброс вещества
Generation of Electricity
Generation of electrical power is a process whereby energy is transformed into an electrical form. There are several different transformation processes, among which are chemical, photo-voltaic, and electromechanical. Electromechanical energy conversion is used in converting energy from coal, petroleum, natural gas, uranium into electrical energy. Of these, all except the wind energy conversion process take advantage of the synchronous AC generator coupled to a steam, gas or hydro turbine such that the turbine converts steam, gas, or water flow into rotational energy, and the synchronous generator then converts the rotational energy of the turbine into electrical energy. It is the turbine-generator conversion process that is by far most economical and consequently most common in the industry today.
The AC synchronous machine is the most common technology for generating electrical energy. It is called synchronous because the composite magnetic field produced by the three stator windings rotate at the same speed as the magnetic field produced by the field winding on the rotor. A simplified circuit model is used to analyze steady-state operating conditions for a synchronous machine. The phasor diagram is an effective tool for visualizing the relationships between internal voltage, armature current, and terminal voltage. The excitation control system is used on synchronous machines to regulate terminal voltage, and the turbine-governor system is used to regulate the speed of the machine. However, in highly interconnected systems one machine will usually be assigned as the so-called "swing machine", and which generation may be increased or decreased to compensate for small changes in load, thereby maintaining the system frequency at precisely 50 or 60 Hz. Should the load dramatically change, as which happens with a system separation, then a combination of "spinning reserve" and the "swing machine" may be used by the system's load dispatcher.
The operating costs of generating electrical energy is determined by the fuel cost and the efficiency of the power station. The efficiency depends on generation level and can be obtained from the heat rate curve. We may also obtain the incremental cost curve from the heat rate curve. Economic dispatch is the process of allocating the required load demand between the available generation units such that the cost of operation is minimized. Emission dispatch is the process of allocating the required load demand between the available generation units such that air pollution occurring from operation is minimized.
Exercise 9. Find pairs of words with similar meanings.
Far, common, graph, to happen, complicated, to distribute, controller, remote, to couple, general, to connect, to allocate, composite, dispatcher, curve, to occur.
Exercise 10. Match each of these terms with the correct description.
1. rotor
2. load
3. turbine
4. generator
5. frequency a) an engine or motor in which the pressure of a liquid or gas, usu. at very high temperature, drives a special wheel, producing a circular movement.
b) a device that converts mechanical energy to electrical energy.
c) a non-stationary part of an alternator or electric motor, operating with a stationary element called the stator.
d) a power output (as of a power plant) or power consumption (as by a device).
e) the number of complete alternations per second of an alternating current.
Exercise 11. Read the text and ask five questions on it.
bulk transmission – большая пропускная способность
load center – центр нагрузки, центр потребления электроэнергии
overhead – воздушный
predominantly – преимущественно
acquisition – приобретение, получение
to dissipate – растрачивать
to occur – происходить, случаться
electric arcing – возникновение электрической дуги
rotor angle – угол наклона ротора
excessive – чрезмерный
to exceed – превосходить, превышать
to damp – уменьшать
to violate – нарушать
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reed - 6 лет назад
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