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Bae Chi
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Minh Hà
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nguyễn mạnh tuấn
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Hà Đức Thọ
5 tháng 6 2015 lúc 0:27

+ Gia tốc: \(a=-\omega^2x\Rightarrow x=-\frac{a}{\omega^2}=-\frac{-3000}{\left(10\pi\right)^2}=3cm\)

+ Ta có: \(x=A.\cos\left(\frac{\pi}{3}\right)=3\Rightarrow A=6cm\)

+ Vận tốc: \(v=-\omega A\sin\varphi=-10\pi.6.\sin\frac{\pi}{3}-30\sqrt{3}\pi\left(\frac{cm}{s}\right)\)

 

Thu Hà
5 tháng 6 2015 lúc 9:36

Mình cũng ra x = 3cm

nguyễn mạnh tuấn
5 tháng 6 2015 lúc 21:43

ok mình hiểu r. tại cứ nhầm x là A nên tính ra =6

cảm ơn bạn nhé.

2@2@
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Nguyễn Minh Anh
16 tháng 1 2022 lúc 16:48

1. Rice is grew in India.

2. This computer is made in USA.

3. Cheese is made from milk.

4. The house is painted every year.

5. The garage is cleaned every week.

6. Coffee is exported to 20 countries.

7. Tea is imported from Brazil.

8. English is spoken everywhere.

9. Cars are not made here.

10. The monkeys are fed twice a day.

Lihnn_xj
16 tháng 1 2022 lúc 16:57

III.               PAST SIMPLE: 

1.       Tolstoy wrote “ War and Peace ”. => " War and Peace " was written by Tolstoy………………………………………………..

2.       Hemingway didn’t write “ Hamlet ” => " Hamlet " didn't written by

Hemingway…………………………………………….

3.       Someone built that house in 1930.=> That house was built in 1930………………………………………………

4.       Bob Smith built this house. => This house was built by Bob Smith………………………………………………………

5.       We invited 50 people to the party.=> 50 people were invited to the party……………………………………………….

6.       They open the factory at 9 o’clock.=> The factory was opened at 9 o'clock ………………………………………………

7.       They posted all the letters yesterday. => The letters were posted yesterday…………………………………………..

8.       James Watt invented the steam engine.=> The steam engine was invited by James Watt……………………………………….

9.       Columbus discovered America in 1490.=> America was discovered in 1490 ………………………………………..

10.    People finished building Thang Long Bridge in 1985.=> Building Thang Long Bridge was finished in 1985 …………………………

Bae Chi
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Cát Tường Anh Nguyễn
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Đỗ Thanh Hải
26 tháng 11 2021 lúc 22:35

1 to start

2 wash - go - to play

3 stay

4 making

5 stay

6 to train

7 to know

8 to smoke

Bae Chi
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minh nguyet
23 tháng 12 2021 lúc 15:15

1.                  Helen (visit) __is visiting_____________ the museum now.

è    _____The museum is being visited by Helen now_____

2.                  We (use) ___are using____________ the computer at the moment.

è    ___The computer is being used by them at the moment___________

3.                  I (fix) _____am fixing__________ my bike right now.

è    _______My bike is being fixed by me right now_________________

 

Ánh Nhật
23 tháng 12 2021 lúc 15:13

1. is visiting    2. are using     3. am fixing

Tô Hà Thu
23 tháng 12 2021 lúc 15:16
Jessica Jung
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Hoa 2706 Khuc
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Nguyễn Quang Minh
7 tháng 4 2022 lúc 19:58

nKMnO4 = 15,8 : 158 =0,1 (mol)
pthh : 2KMnO4 –t-> K2MnO4 +MnO2+O2
            0,1                                            0,05
=>V=VO2 =0,05 . 22,4=1.12(l)