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Абсолютный показатель преломления вещества 1,54.Вопрос:Чему равна скорость света в веществе ???
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Предмет:
Физика -
Автор:
lizzydickerson - 5 лет назад
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Ответы 2
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Спасибо)Сама уже смогла решить.
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Автор:
tessahudson - 5 лет назад
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абсолютный показатель преломление это отношения скоростей света в вакууме и в среде:n = c/vотсюда :v = c/nv = 3*10∧8/1,54=194805194.805 м/с округлишь сама
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Автор:
francisco71 - 5 лет назад
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У трьох шостих класах школи навчається 81учень. Кількість учнів 6-б класу становить 80% кількості учнів 6-а класу,а кількість учнів 6-в класу становить 50%кількості учнів 6-а і 6-б класів разом. Скільки учнів у кожному класі?
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Предмет:
Математика -
Автор:
goose29 - 5 лет назад
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Ответов:
1 -
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Текст
A)
The Native Americans were the first inhabitants of the Americas. They were the first environmentalists. To them, every part of the natural world, whether it was an animal, vegetable or mineral, had a spirit. American Indians viewed nature as a gift from the Gods, which should be treated with great respect at all times. They gratefully took food and clothes from nature, but they never exceeded the limits.
B)
The Native Americans inhabited different regions of the country and there is no reliable evidence of where they come from. The Native Americans claim that they have lived there since the beginning of time. There is also an opinion that they migrated there in prehistoric times via the Bering Strait Land Bridge. Some researchers believe that they came from Siberia or Asia. All these are still only hypotheses.
C)
When Christopher Columbus landed, he thought he had reached India and called all the native people Indians. The name, though it was wrong, stuck to the local people and has been used to the present day. In fact, there were lots of different independent tribes with their own distinct cultures and languages. But they all became known to common public as Indians.
D)
The Pilgrims, who sought religious freedom and crossed the Atlantic in the Mayflower in 1620, were treated kindly by the Indian tribe in Massachusetts. The native inhabitants generously shared their knowledge with the newcomers. They showed the Pilgrims how to plant corn, beans, and pumpkins, and where to hunt and fish. In fact, the Indians were excellent fishermen and even invented a special canoe. A widely celebrated holiday of Thanksgiving still reminds us of this gesture of goodwill.
E)
However, this harmonious relationship was short-lived. Native Americans had lived in isolation for centuries and they had no protection against such European diseases as smallpox, typhus and measles. Unfortunately, the newcomers introduced these diseases to them. For those in regular contact with European settlers, the effects were destructive: it is estimated that in some tribes up to 90% of Native Americans died during the first century of contact with the Europeans.
F)
Then things moved from bad to worse. European settlers drove the Indians away from their lands as settlers moved westward. Treaties were often signed after Indian leaders were given alcohol. Whether through war or lies, the Native Americans' lands were systematically taken. Indians were forced to move to separate areas, known as Indian Reservations. Most of the lands were unsuitable for cultivation and didn't have any valuable resources.
G)
Many visitors to the USA ask about how they can visit an Indian Reservation. They could hardly do it! Nowadays very few natives live in reservations or in the traditional dwellings of their ancestors. Most Indian families live in homes that are not very different from any other houses in the USA, and their lifestyle does not differ much from contemporary American lifestyle.
Заголовок
1)
Like the others do
2)
Unclear origin
3)
Eco-friendly people
4)
Keeping traditions
5)
A warm welcome
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Dishonest business
7)
A long-lasting name mistake
8)
A deadly misfortune-
Предмет:
Английский язык -
Автор:
rubye4f8 - 5 лет назад
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Ответов:
1 -
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