Bài 5. Biết 10 lít cát có khối lượng 15kg. a. Tính khối lượng riêng của cát . b. Tính thể tích của 1 tấn cát.

2 câu trả lời

Đáp án:a) khối lượng riêng của cát = 1.5(kg/lít)

 b) 2000/3

Giải thích các bước giải:a) khối lượng riêng = khối lượng / thể tích

Thay số vào ta được

Khối lượng riêng = 15/10= 1,5(kg/lít)

b)1000/(15/10) = 2000/3

Đáp án:

 D=1500kg/m^3

Giải thích các bước giải:
\[V = 10lit = 0,01{m^3};m = 15kg\]

a> khối lượng riêng: 
\(D = \frac{m}{V} = \frac{{15}}{{0,01}} = 1500kg/{m^3}\)

b> thể tích: 
\(D = \frac{{m'}}{{V'}} =  > V' = \frac{{m'}}{D} = \frac{{1000}}{{1500}} = \frac{2}{3}{m^3}\)

 

Câu hỏi trong lớp Xem thêm

II. Khoanh tròn vào câu trả lời đúng 1. Where his wife (be)? a. am b. is c. are d. be 2. Jack (wear) suit today. a. is wearing b. are wearing c. am wearing d. wears 3. The weather (get) warm this season. a. gets b. are getting c. is getting d. are gets 4. My kids (be)…………. downstairs now. They (play) chess. a. am/ am playing b. is/is playing c. are/are playing d. be/ being 5. Look! The train (come)………………… a. are coming b. is coming c. are coming d. is coming 6. Alex always (borrow) ………………..me cash and never (give)……………….. back. a. is borrowing/ giving b. are borrowing/ giving c. borrows/ giving d. borrow/ giving 7. While I (do)……………….. my homework, my sister (read) ……………….. newspapers. a. am doing/ is reading b. are doing/ is reading c. is doing/ are reading d. am doing/ are reading 8. Why at me like that? What happened? a. do you look b. have you looked c. did you look d. are you looking 9. I in the bathroom right now. a. am being b. was being c. have been being d. am 10.It late. Shall we go home? a. is getting b. get c. got d. has got 11.-“Are you ready, Belle?” “Yes, I ” a. am coming b. come c. came d. have came 12.-Look! That guy to break the door of your house. a. try b. tried c. is trying d. has tried III. CHIA ĐỘNG TỪ Ở THÌ HIỆN TẠI ĐƠN HOẶC HIỆN TẠI TIẾP DIỄN: 1. The children (play) outside now. 2. She usually (read) the newspaper in the morning. 3. I (do) my homework now. 4. I (eat) my dinner now. 5. (you / want) a pizza? 6. They (watch) TV now. 7. I (not / like) spaghetti. 8. The baby (sleep) now. 9. My mother usually (cook) dinner in the evening. 10. He (write) a letter to his pen-friend every month. 11. She (not / like) football. 12. Mary (listen) to music now. 13. Tom usually ……………………(drink) coffee, but he (drink) tea now. 14. We (go) to the disco tonight.

0 lượt xem
1 đáp án
2 phút trước