bn đăng câu hỏi này làm gì vậyLinh Trần

Một vật đặt trên mặt phẳng nghiêng (góc nghiêng α = 30 ∘ ), được truyền một vận tốc ban đầu v 0 = 20   c m / s  (hình vẽ dưới). Hệ số ma sát giữa vật và mặt phẳng nghiêng là 0,3. Tính độ cao lớn nhất H mà vật đạt tới.

A. 0,451 m.                    

B. 0,134 m.                    

C. 0,342 m.                    

D. 1,145 m.

Một êlectron được thả không vận tốc đầu ở sát bản âm, trong điện trường đều giữa hai bản kim loại phẳng, tích điện trái dấu. Cường độ điện trường giữa hai bản là 1000 V/m. Khoảng cách giữa hai bản là 1cm. Tính động năng của êlectron khi nó đến đập vào bản dương.

A.  1 , 6 . 10 - 18 J

B.  2 , 6 . 10 - 16 J

C. - 1 , 6 . 10 - 18 J

D.  3 , 6 . 10 - 18 J

Read the following passage and mark the letter A, B, C or D on your answer sheet to choose the best answer for each of the question from 43- 50

Of all the aspirations which make up the American Dream, perhaps the most prominent is to own one’s own home. Americans are very proud of their homes and spend a great deal of time maintaining their houses and keeping the property in good condition. A man's home is often called his castle, and the hours spent keeping his fortress safe and secure become one of his greatest pleasures.

If a home is in an especially fashionable neighborhood, the owners may consult an interior decorator to give the home a certain coordinated appearance. If there is a large back yard, great care may be spent in having it properly landscaped with exotic trees, shrubs and plants.

It is almost a certainty that you should be the first visitor to an American home, you will be taken on a grand tour of the premises. The owner will take great pride in showing to you the place he calls home. Every closet, every cabinet and closed door will be opened so that you can actually see the extent and value of his home. You will even be taken into the father's den and the mother's sewing room. These are special rooms for the respective man and woman of the house to insure their privacy. They may be off-limits to the rest of the family but, for the visitor they are open to scrutiny and inspection.

It is, of course, considered polite on the tour to comment favorably on each room picking out its most salient, important feature, such as the special view from the window, the vaulted ceiling in the foyer or the exotic choice of wallpaper in the bathroom.

The finished basement is a special cause for pride for the family with its exercise room, video games, carpenter shop and launderette. In most homes it is here that the family entertains itself in the evening while the rest of the house becomes more of a showcase. On your tour you may be reminded of the hours the owners had spent "fixing up the house" so it would be "nice for the kids to bring over their friends". You may even sense a feeling of competition in knowing that they have not only "kept up with the Joneses" but also have far surpassed them.

The tour will terminate after an hour or so somewhere on the back lawn next to the two-car air-conditioned garage where you may be treated to a snack and light refreshment.

Showing off one's home is more than an exercise in vanity. It is a tribute to one's accomplishment. It is a way of saying that a man has been a good provider for his family and that he has realized one of his dreams.

What is often called “castle” for many Americans?

A. One's own home

B. Mc Donald's

C. Disneyland

D. The White House

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

Her fiancé is said to graduate from Harvard University five years ago

A. fiances

B. is

C. to graduate

D. years

Give the correct form or tense of the verbs in the brackets.

1. My uncle (not/ be) ……………………………. out of his house since he (buy) ………………………… a color TV.

2. I don’t think I (go) ............................... out tonight. I (be) .......................... too tired.

3. John (wash) .............................. his hands. He (just/ repair) ...................................... the TV set.

4. Tell him (bring) .................................. his bike inside. If he (leave) ........................... it there, someone (steal) ....................................... it.

5. Where (you/ spend) ........................................ your summer holiday last year?

Một cái hòm khối lượng m = 40   k g  đặt trên mặt sàn nhà. Hệ số ma sát trượt giữa hòm và sàn nhà là μ t = 0 , 2 . Người ta đẩy hòm bằng một lực F = 200   N theo phương hợp với phương nằm ngang một góc  α = 30 ∘ , chếch xuống phía dưới (Hình vẽ). Gia tốc của hòm là

A.  1 , 87   m / s 2           

B. 2 , 87   m / s 2     

C. 0 , 87   m / s 2

D. 3 , 87   m / s 2

Để điều chế trực tiếp anđehit axetic có thể đi từ chất nào sau đây?

A. Etan.

B. Etanol.

C. Axit axetic.

D. Natri axetat

Read the following passage and mark the letter A, B, C or D on your answer sheet to choose the best answer for each of the question from 43- 50

Of all the aspirations which make up the American Dream, perhaps the most prominent is to own one’s own home. Americans are very proud of their homes and spend a great deal of time maintaining their houses and keeping the property in good condition. A man's home is often called his castle, and the hours spent keeping his fortress safe and secure become one of his greatest pleasures.

If a home is in an especially fashionable neighborhood, the owners may consult an interior decorator to give the home a certain coordinated appearance. If there is a large back yard, great care may be spent in having it properly landscaped with exotic trees, shrubs and plants.

It is almost a certainty that you should be the first visitor to an American home, you will be taken on a grand tour of the premises. The owner will take great pride in showing to you the place he calls home. Every closet, every cabinet and closed door will be opened so that you can actually see the extent and value of his home. You will even be taken into the father's den and the mother's sewing room. These are special rooms for the respective man and woman of the house to insure their privacy. They may be off-limits to the rest of the family but, for the visitor they are open to scrutiny and inspection.

It is, of course, considered polite on the tour to comment favorably on each room picking out its most salient, important feature, such as the special view from the window, the vaulted ceiling in the foyer or the exotic choice of wallpaper in the bathroom.

The finished basement is a special cause for pride for the family with its exercise room, video games, carpenter shop and launderette. In most homes it is here that the family entertains itself in the evening while the rest of the house becomes more of a showcase. On your tour you may be reminded of the hours the owners had spent "fixing up the house" so it would be "nice for the kids to bring over their friends". You may even sense a feeling of competition in knowing that they have not only "kept up with the Joneses" but also have far surpassed them.

The tour will terminate after an hour or so somewhere on the back lawn next to the two-car air-conditioned garage where you may be treated to a snack and light refreshment.

Showing off one's home is more than an exercise in vanity. It is a tribute to one's accomplishment. It is a way of saying that a man has been a good provider for his family and that he has realized one of his dreams.

What is considered the biggest reachable dream for most Americans?

A. To be president of the United States of America 

B. To be rich and famous for fifteen minutes 

C. To be a movie or rock star 

D. To own one's own house

Số đồng phân hiđrocacbon thơm ứng với công thức phân tử C 8 H 10  là :

A. 5.

B. 2.

C. 3.

D. 4.