Một thùng phuy đựng dầu hình trụ tròn có bán kính đáy 60cm, chiều cao là 220 cm. a.Tính thể tích của dầu trong thùng khi bơm đầy. b.Diện tích vỏ kim loại cần làm ra cái thùng phuy trên là bao nhiêu mét vuông

1 câu trả lời

Đáp án:

a) Thùng có kích thước là hình trụ tròn có 

$\begin{array}{l}
r = 60cm;h = 220cm\\
 \Leftrightarrow V = \pi .{r^2}.h\\
 = 3,{14.60^2}.220\\
 = 2486880\left( {c{m^3}} \right)\\
 = 2486,88\left( {d{m^3}} \right)\left( {lit} \right)
\end{array}$

Vậy thể thích của dầu khi bơm đầy thùng là $2486,88\left( {lit} \right)$

b)

Diện tích xung quanh hình trụ là:

$\begin{array}{l}
{S_{xq}} = 2\pi .r.h\\
 = 2.3,14.60.220\\
 = 82896\left( {c{m^2}} \right)
\end{array}$

Diện tích nắp và đáy thùng là:

$S = 2\pi {r^2} = 2.3,{14.60^2} = 22608\left( {c{m^2}} \right)$

Tổng diện tích vỏ kim loại là:

$105504\left( {c{m^2}} \right) = 10,5504{m^2}$

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I.  MULTIPLE CHOICE (8.0 points)

Mark the letter A, B, C, or D to indicate the word whose underlined part is pronounced differently front that of the rest in each of the following questions.

1. A. oceanic    B. remote    C. occasion    D. metro

2. A. festival    B. cultural    C. sculpture    D. virtual

Mark the letter A, B, C, or D to indicate the word that differs from the other three in the position of primary stress in each of the following questions.

3. A. external    B. determine    C. mysterious    D. customer

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Mark the letter A, B, C, or D to indicate the underlined part that needs correction in each of the following questions.

5. Now that the stress of examinations are over, we can go somewhere for our holiday.

                     A                     B                     C                     D

6. The English summer course will start in May 29th and finish in August.

                     A                     B                     C                     D

7. There were so a lot of people trying to leave the burning building that the police

             A                B             C

had a great deal of trouble controlling them.

                   D

Mark the letter A, B, C, or D to indicate the correct answer to each of the following questions.

8. The earthworm is a worm _______in moist, warm soil in many geographical areas.

    A. where is it found       B. is found

    C. and found it               D. which is found

9. Our flight from Amsterdam to London was delayed    the heavy fog.

    A. as a result     B. on account     C. instead of     D. due to

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    A. productive     B. unproductive     C. producing     D. unproducing

11. A good clock always keeps_______ time.

    A. certain    B. accurate    C. true    D. serious

12. It seems that the world record for this event is almost impossible to_______.

    A. meet    B. compare    C. beat    D. balance

13. The soldier was punished for_______ to obey his commanding officer's order.

    A. refusing    B. regretting    C. objecting    D. resisting

14. It is believed that she'll be a billionaire by the time she_______ forty.

    A. is    B. was    C. will be    D. would be

15. Some of the passengers spoke to reporters about their_______ in the burning bus.

    A. occasion    B. happening    C. event    D. experience

16. _______the rise in unemployment, people still seem to be spending more.

    A. Nevertheless    B. Meanwhile    C. Despite    D. Although

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