Chọn kết luận sai trong các kết luận sau, khi so sánh ba viên bi sắt, chì, nhôm có cùng thể tích. * 1 điểm A. Bi nhôm có khối lượng nhỏ nhất. B. Bi sắt có khối lượng lớn hơn bi nhôm. C. Bi chì có khối lượng nhỏ hơn bi sắt. D. Bi chì có khối lượng lớn nhất.

2 câu trả lời

Ta có :

`text{Khối lượng riêng của chì là : 11300 kg/m³}`

`text{Khối lượng riêng của sắt là : 7800 kg/m³}`

`text{Khối lượng riêng của nhôm là : 2700kg/m³}`

`text{Ta có : công thức tính khối lượng : m = D.V}`

`text{Mà sắt , chì và nhôm có cùng thể tích }`

`text{nên : Chì có khối lượng lớn nhất}`

         `text{Sắt có khối lượng nhỏ hơn Chì}`

       `text{Nhôm có khối lượng nhỏ nhất}`

⇒`text{C : Bi chì có khối lượng nhỏ hơn bi sắt}`

Đáp án:

 C

Giải thích các bước giải:

 Ta có, khối lượng riêng các chất

\[{D_{chi}} > {D_{sat}} > {D_{n\hom }}\]

Khối lượng các bi: m = D.V

Mặt khác: 

\[{V_{chi}} = {V_{sat}} = {V_{n\hom }}\]

Nên

\[{m_{chi}} > {m_{sat}} > {m_{n\hom }}\]

Vậy kết luận sai: C

Câu hỏi trong lớp Xem thêm

I. Circle the correct one. “Too or Enough” 1) This car is too/enough old. We cannot go anywhere. 2) This book is too/enough thick for me to read. 3) That dress is cheap too/enough to buy. 4) This question is too/enough complicated to answer. 5) Everybody is too/enough excited about the holiday to focus on their work. 6) I can join that club. I’m young too/enough. 7) She can’t come with us to the bar. She’s too/enough young. 8) We have too/enough eggs to make a cake. 9) Do we have too/enough time to catch the bus? 10)This boy is too/enough noisy. I can’t study! 11)Mary’s room is too/enough dirty. Her mom is angry. 12)Tom is tall too/enough to join a basketball team. 13)This bag is too/enough heavy. I can’t carry it. II. Complete with “too” or “enough”. 1- She is clever ........................ to pass the test. 2- The skirt is ........................ long for you. 3- Kate is .......................young to drive a car. 4- There is ......................... meat in the fridge for the whole week. 5- I didn’t work hard ........................ to pass the exam. 6- We can’t buy the car because it is .......................expensive. 7- He can’t sleep because he drinks .......................much coffee. 8- Are you tall ...................... to reach that shelf? 9- They often take the bus to school because it’s ................... far to walk. 10- She isn’t fast ...................... to win the race. 11- There’s .......................food for everyone to eat. 12- She isn’t speaking clearly ................for me to understand. III. Complete the sentences with “too – enough” by using the words given. 1) I don’t want to eat that soup. It is _______________________. ( cold ) 2) She can’t come to party with us. She isn’t _______________________. ( old ) 3) They need much money. That car is _______________________ to buy. ( expensive ) 4) We don’t need to worry about the food. It is _______________________. (fresh ) 5) I missed the bus because I got up _______________________. ( late ) 6) I cannot buy that dress. It isn’t _______________________ for me to buy. ( cheap ) 7) I cannot climb that mountain. It is _______________________. ( high ) 8) You should help your sister. She is _______________________ to eat herself. (young) 9) It is _______________________ to see the way. ( foggy ) 10) He is _______________________ to win the race. ( fast ) 11) He is _______________________ to be the headmaster. ( qualified ) 12) Don’t want any help from him. He is _____________________ to help anyone. (rude) 13) The movie was _______________________. I couldn’t watch it. ( boring ) 14) Ben is _______________________ to solve the problems. He never studies. ( lazy ) 15) The questions were _______________________ to solve. ( difficult ) 16) Jeremy is _______________________ to talk people. ( shy ) 17) Ashley is _______________________ to pass the test. ( hardworking ) 18) I can’t wear this t-shirt. It is _______________________. ( small ) Giúp mk vs, tuy ns dài nhưg rấc cần sự giúp đỡ! Mk cần 2 bn lm ạ, bn nào có sức thì làm 2 bài, còn bn còn lại lm 1 bài a

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