Một chất điểm thực hiện chuyển động thẳng trên trục $Ox$ với vận tốc được cho bởi công thức: $v\left(t\right)=3t^2+4t\text{ (}m/s)$ , ( $t$ là thời gian). Biết rằng tại thời điểm bắt đầu của chuyển động, chất điểm đang ở vị trí có tọa độ $x=3$ . Tọa độ của chất điểm sau $1$ giây chuyển động là?

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Một số câu hỏi khác có thể bạn quan tâm.

• Choose the best answer for the following sentence:

  Young guests often have willing ________________ in any kinds of entertainment.

    

• Choose the correct sentence which is built from the words and phrases given:

  everyone / like / her / because / she / kind / caring / teacher /.
  
  

•  Choose the best answer for the following sentence:

  It’s interesting at parties to see how people ____________  socially.

   

• Choose the best answer for the following sentence:

  It is a waste of time ______________ such a boring party.

   

• Choose the best answer for the following sentence:

  It is high time we ________________ preparations for our farewell party next week.

   

•  Choose the best answer for the following sentence:

  I intend ____________________ this book by the end of March.

    

•  Choose the best answer for the following sentence:

  We practice ______________ English every day because we want ________________ it as soon as possible.

   

•  Choose the best answer for the following sentence:

  I don’t mind ________ . We have got time _________ this.

   

• Read the following passage and choose the best answer for each blank:

           Before the (1)__________ of the postage stamp, it was difficult to send a letter to (2)_________ country. The sender paid for the letter to travel in his or her own country. Then the person in another country paid (3)_________ that part of the trip. If a letter crossed several (4)___________ , the problem was worse.
           Rowland Hill, a British teacher, had the idea of a postage stamp with glue on the back. The British post office made the first (5)__________ in 1840. They were the Penny Black and the Twopence Blue. A person bought a stamp and put it on a letter. The post office (6)__________ the letter. When people (7)_______ letters, they didn’t have to pay anything. The letters were paid. Postage stamps became universal in Great Britain immediately. Other countries started making their postage stamps very quickly. Today post offices in every country sell beautiful stamps. (8)_________ stamps is one of the cheapest hobbies in the world, and every stamp (9)________ knows (10)_________ the Penny Black and the Twopence Blue.

   

  1. A. invention                B. arrival                   C. transmission                D. delivery
  2. A. other                      B. the other              C. another                        D. others
  3. A. to                           B. for                         C. with                              D. about
  4. A. cities                      B. post offices            C. people                         D. countries
  5. A. envelopes              B. parcels                  C. stamps                         D. postcards
  6. A. transmitted            B. delivered               C. subscribed                   D. received
  7. A. sent                       B. faxed                     C. delivered                     D. received
  8. A. Delivering               B. Collecting              C. Selling                          D. Buying
  9. A. collecting                B. collector                C. collection                      D. collected
  10. A. about                   B. of                          C. on                                 D. to

   

•  Choose the best answer for the following sentence:

  The higher you hope _______________. The more you must risk ____________ .