Поезд массой 420 т, трогаясь с места через 18 с набрал скорость 28км/ч. Определите силу тяги

Поезд массой 420 т, трогаясь с места через 18 с набрал скорость 28км/ч. Определите силу тяги
- Предмет:
  Физика
- Автор:
  reesebdwt
- 5 лет назад

Ответы 2

Лучший ответ будет позже
- Автор:
  rapunzel6p67
- 5 лет назад
- 0
Дано:
m=420т
t=18c
v0(ноль чуть ниже v)=0
V=28км/ч=8м/с
___________
F-?
Решение:
A=v/t (надеюсь понимаете что это дробь)
Так как его начальная скорость равна 0, по 2закону Ньютона
Получаем следующие равенство:
a=F/m
F/m=v/t
Отсюда следует такое решение:
F=mv/t =420000 кг•8м/с /(дробью) 18с= 123кПа
вроде так
- Автор:
  parker583
- 5 лет назад
- 0
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Переведите без переводчика пожалуйста текст A GIGGLE BOX AND A LEAKY FAUCET:
A GIGGLE BOX, A LEAKY FAUCET, AND A FOGHORN

Every day after lunch Mrs. Jewls read a story to the class.

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The last book Mrs. Jewls had read was a story about a pig and spider. The pig was really cute and the spider was very wise.

Dana thought it was a horrible book. It made her laugh too much. Everyone else laughed too, but the problem was that Dana always kept laughing long after everyone else in the class had stopped. It was very embarrassing . And sometimes she broke out laughing at a part that wasn't even funny because she remembered something funny that had happened earlier.

John called her a giggle box.

That only made her laugh harder.

Once she broke out laughing in the middle of an arithmetic test because she remembered something funny the pig had said.

"There goes the giggle box," said John.

She hated John.

But that wasn't the worst part of the book. In the end, the spider died.

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John called her a leaky faucet. "Somebody better call a plumber ' to fix the leaky faucet," he said.

She laughed through her tears. She hated John.

Once in music, they had learned a song about a dragon. When the song begins the dragon is very brave, but then he loses his only friend, so he isn't brave anymore. He just goes back to his cave, where he is sad and lonely for the rest of his life.

The song always made Dana cry. Every interval John and Joe would chase after her, singing it. She'd run across the playground with her hands over her ears and tears falling down her face.

The bell rang. Lunch was over. Dana nervously walked up the stairs to Mrs. Jewls's room. Mrs. Jewls would start a new book today. She hoped it wouldn't be funny or sad. She hoped Mrs. Jewls would read a dull story with no jokes.

When she got to class, John and Joe were standing by her desk waiting for her.

"Happy birthday, Dana," said John. He was holding a present. It was wrapped in green paper and had a pink bow. "But it's not my birthday," said Dana. "Well, that's okay," said John. "You can have it anyway. Since I'm always teasing you." He and Joe smiled.

Dana eagerly tore off the wrapping paper. Maybe John wasn't so bad after all, she thought. It was a box of tissues. John and Joe laughed hysterically. "That's not funny!" said Dana. She raised her fist and started to chase after them.
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Поезд массой 420 т, трогаясь с места через 18 с набрал скорость 28км/ч. Определите силу тяги

Ответы 2

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