Предмет: Физика, автор: Svetlankoooo

Падающий вертикально шарик массой 0,2 кг ударился об пол и подпрыгнул на высоту 0,4 м. Найдите среднюю силу, действующую со стороны пола на шарик, если длительность удара 0,01 с, к моменту удара об пол скорость шарика 5 м/с

Ответы

Автор ответа: nelle987

Скорость после удара можно найти из уравнения

$<var>v_1^2=2gH\\ v_1=\sqrt{2gH}</var>$

$<var>\bar{F}=\dfrac{\Delta p}{\Delta t}=\dfrac{mv_0-mv_1}{\Delta t}=\dfrac{m(v_0-\sqrt{2gH})}{\Delta t}=\dfrac{0.2\cdot(5-\sqrt{20\cdot0.4})}{0.01}\\=43.4\text{ kN}</var>$

Предыдущий вопрос

Следующий вопрос

Интересные вопросы

Предмет: Русский язык, автор: sofffka263

Разберите по составу и дайте характеристику
Предложения в конце

2 года назад

Предмет: Окружающий мир, автор: alisabernackay

самый засушливый район Крыма

2 года назад

Предмет: Английский язык, автор: Altun233

1. Complete the sentences. Use ‘ll or won't.
1. Amy's brother is thirteen. He____ be fourteen on his next birthday.
2. I bought a lottery ticket, but I ____ win
3. My dad is thirty-nine. He _Упражнение___ be forty on his next birthday.
4. My sister Mary is fifteen. She ____ be sixteen until next year.
5. My brother's clever. He____ pass all his exams.
6. It's raining now. But it____ be sunny later.
7. Debbie and Bob are always late. They____ arrive until eight o'clock.

Упражнение 2. Что Вы будете делать на летних каникулах. What will you do in the summer holidays? Use the words from the box.
go to the theatre, go to the river, go to the zoo, collect pebbles, read books, read magazines, watch films, make friends, go sunbathing, write a diary

Упражнение 3. Вы на острове, что Вы будете делать? You are on an island. What do you think you'll do?
1. Will you live in a cave or in a village?
I think I'll live in a cave.
2. Will you sleep on the grass or in the tree?
I think I'll ________________ .
3. Will you eat caterpillars or snakes?
___________________________
4. Will you go fishing or collect fruit?
___________________________
5. Will you wash in the sea or in the river?
___________________________
6. Will you ride a horse or an ostrich?
___________________________
7. Will you make friends with dolphins or with parrots?
___________________________
8. Will you drink milk or water?
___________________________

Упражнение 4. Прочитайте текст, ответьте на вопросы.
My name is Tanya. I am a pupil. Tomorrow I will not go to school. It will be Sunday. Father and Mother will not be at home. They will go to see their friends.
Answer the questions:
1. Why won't Tanya go to school tomorrow?
2. Will her Mother and Father be at home?
3. Where will they go?
4. What will Tanya do when her parents go to see her friends?

Упражнение 5. Рaскройте скобки, используя Future Indefinite.
I ___________ (to be) at home. I ___________ (to invite) my friend Nina to come home. We_________ ( play). She __________ ( be) Big Grey Angry Wolf and I ________ ( be) Litlle Red Riding Hood. And who ________ (be) Granny, who lives in the forest. I think we __________ (invite) Kate to come and play with, us too.