Một vật có khối lượng 50 g chuyển động thẳng đều với vận tốc 50 cm/s thì động lượng của vật là bao nhiêu?

Một ôtô đang chuyển động đều với vận tốc v = 15 m /s trên mặt đường nằm ngang. Biết công suất của động cơ ô tô là 60 kW. Lực kéo của động cơ ô tô là bao nhiêu?

II. Rewrite each of these sentences without changing its original meaning

1.The scientists are studying the problem carefully.

The problem ______________________________________________.

2. Somebody had already reported the accident before I phoned.

The accident ______________________________________________.

3. These students should have finished the tasks by the time their teacher came back.

The tasks _________________________________________________

4.Our heating isn’t working and I feel cold.

If our heating _______________________________________________.

5. You can’t make a cake without flour.

Unless ____________________________________________________.

6. The fire destroyed the forest completely.

The forest __________________________________________________.

7.You must hurry or we'll miss the train.

Unless we __________________________________________________.

8. People must not leave bicycles in the hall.

Bicycles____________________________________________________.

II. Rewrite each of these sentences without changing its original meaning

1.The scientists are studying the problem carefully.

The problem ______________________________________________.

2. Somebody had already reported the accident before I phoned.

The accident ______________________________________________.

3. These students should have finished the tasks by the time their teacher came back.

The tasks _________________________________________________

4.Our heating isn’t working and I feel cold.

If our heating _______________________________________________.

5. You can’t make a cake without flour.

Unless ____________________________________________________.

6. The fire destroyed the forest completely.

The forest __________________________________________________.

7.You must hurry or we'll miss the train.

Unless we __________________________________________________.

8. People must not leave bicycles in the hall.

Bicycles__________________________________________________.

I. Choose one word or phrase - a, b, c or d - that best completes the sentence or substitutes for the underlined word or phrase

1____________ is a chemical used for killing weeds.

A. Pesticide B. Herbicide C. Fertilizer D. Antibiotic

2. Sperm whale population are at risk due to hunting.

A. in extinction B. in danger C. on the decrease D. in fewness

3. What would Tom do if he ______ the truth?

A. would know B. has know C. knows D. knew

4. _____________ you, I would think twice about that decision. It could be a bad move.

A. If I am B. Should I be C. Were I D. If I had been

5. An announcement about the eight o'clock flight to Chicago ________.

A. has been already made B. has already made

C. has already been made D. already made

6. Many reliable methods of storing information ___________when computers arrived.

A. tend forgotten B. tend to forget

C. tend to be forgotten D. tend being forgotten

7. He would never do anything to _______ the lives of his children.

A. danger B. endanger C. endangered D. dangerous

8. Whales and sharks are carnivores, _______ means they eat meat.

A. this B. that C. it D. which

9. Mary's children are used to ____ after school every day. They don't have to walk home.

A. picking up B. being picked up C. be picked up D. pick up

10. Diaz is a wonderful ballet dancer. She ______ since she was four.

A. had been dancing B. has been danced C. has danced D. was danced

11. Up to now, AIDS have not been _______, and more and more people died of the disease.

A. treated B. concerned C. killed D. stopped

12. She is a famous _______. She is very interested in protecting wild animals from extinction.

A. conserve B. conservationist C. conservation D. Conservational

13. A: I don't know how to use this camera?

B: It's quite easy. ................. you

A. I going to show B. I'll show C. I'm will show D. I'm going to show

14. We....................use herbicides, pesticides and fertilizers that harm the environment

A. should not B. should C. will D. does not

15. The animals are not kept in .............., they can live in their natural environment

A. cages B. house C. hotel D. restaurant

16. The English class ..................................by a lot of students and teachers tomorrow

A. will be attended B. will attend C. attended D. will attended

17: These flowers are fresh. They .................... from the garden

A. have been just picked B. have just been picked

C. have been picked just D. just have been picked

18: You .............. go to bed late. It's not good for your health.

A. mustn't B. should C. shouldn't D. oughtn't

19. I think you ................study hard for the next exam.

A. could B. will C. would D. should

20. The life ......... of sperm whale can be up to seventy years.

A. distance B. period C. length D. span

21. Without plants, most of water would ............................as soon as it falls.

A. run off B. run after C. run away D. run by

22. I still can't believe it! My bicycle................ last night.

A. was stealing B. stolen C. was stolen D. stole

23 It rained all the time, ................was a great pity.

A. that B. what C. which D. who

24. Water can be held on the land by vegetation.

A. plants used as food B. grown tree

C. plants and trees D. the growth of plants

25. The farmer removed some undeveloped trees to improve the growth of the rest.

A. planted B. watered C. eliminated D. fertilized

Một ô tô khối lượng 2 tấn chuyển động đều trên mặt đường nằm ngang. Hệ số ma sát giữa xe và mặt đường là 0,05. Tính công của lực ma sát khi ô tô chuyển động trên một quãng đường 1000m. (g = 10 m/s²)

Một ô tô khối lượng 3,5 tấn bắt đầu chuyển động nhanh dần đều. Biết khi ô tô đi được 25m đạt vận tốc 36km/h, cho hệ số ma sát giữa xe và mặt đường là 0,3; g = 10m/s² .Tính công của lực kéo động cơ.