Một đoàn tàu đang chạy với vận tốc 72 km/h thì hãm phanh chạy chậm dần, sau 10 s vận tốc giảm xuống còn 15 m/s. Hỏi phải hãm phanh trong bao lâu kể từ khi tàu có vận tốc 72 km/h thì tàu dừng hẳn (coi gia tốc không đổi)?

Chia sẻ

Một số câu hỏi khác có thể bạn quan tâm.

• Choose the word whose stress is on the second syllable:

  innocent                 pharmacy                   existence                      pianist

• Choose the best answer for the following sentence:

  Do you think she can ______________ a promise?

• Choose the best answer for the following sentence:

  The Rolling Stones have ____________ pleasure to millions of fans for more than 40 years.
  
  

• Choose the best answer for the following sentence:

  Ann _____________ that she would wait at the bus stop.

• Choose the best answer for the following sentence:

  “How old are you?”
  → They asked her ____________ .
  
  

• Find a mistake in the four underlined parts of the sentence and correct it:

  If I find your pen. I send it to you.

• Find a mistake in the four underlined parts of the sentence and correct it:

  I am very interesting in problems caused by pollution.

• Choose the word that has the underlined part pronounced differently from the rest: 

  comic                  cotton                     post                      economic

• Choose the word that has the underlined part pronounced differently from the rest: 

  health                    think                       toothache                       other

• Choose the word whose stress is on the second syllable:

  important                 politics                    supervise                     concentrate