1) Thoi gian di het quy dao la t= 4s la cai gi = 4s

1) In the near future, the government will instigate new measures to combat...........

A. terrorist     B. terrorism       C. terrorize        D. terror 

Giai thich vi sao 

1) Ket luan nao ( neu duoi day) sai

A. Cac loai dau mo dong vat va thuc vat deu thuoc loai lipit

B. Cac loai dau mo cong nghiep deu thuoc loai lipit

C. Cac loai dau mo cong nghiep khong thuoc loai lipt

D. Cac loai dau mo cong nghiep khong phai la este

1) Trong thanh phan cua mot loai son co cac triglixerit la trieste cua glixerol voi axit C₁₇H₃₁COOH va axit C₁₇H₂₉COOH. Cong thuc cau tao nao khong dung trong cac cong thuc sau:

A. C₁₇H₃₁COOH - CH₂                                                 B. C₆H₅COO-CH₂

     C₁₇H₃₁COOH - CH                                               C₆H₅COO- CH

     C₁₇H₃₃COOH - CH₂                                               C₆H₅COO- CH₂

C.  C₁₇H₃₅CO - CH₂                                                D. C₂H₅COO- CH₂

      C₁₇H₃₅CO - CH                                                     C₂H₅COO - CH

      C₁₇H₃₅CO - CH₂                                                   C₂H₅COO - CH₂

1) Van toc va gia toc khi no dang dao dong o vi tri li do x = 3cm

Tu cong thuc \(\dfrac{x^2}{A^2}+\dfrac{v^2}{\omega^2A^2}=1\) thi lay v = + - \(\sqrt{\left(\left(1-\dfrac{x^2}{A^2}\right)\omega^2A^2\right)}\) hay v > 0 

1) Cho cac phuong trinh dao dong sau:

a) x₈ = 2sin 4πt + 2cos 4πt (cm)

b) x₇ = 3sin ( -5t - \(\dfrac{\Pi}{6}\)) (cm)

c) x₄ = 5cos 2πt + 3 (mm)

Xac dinh bien do, pha ban dau, chu ky cua moi dao dong

1) Cho 14,8g hon hop gom 2 este X va Y co cung CTPT bay hoi chiem the tich la 4,48 lit o dktc. Khi dot chay tao ra CO₂ va H₂O voi so mol bang nhau. Cong thuc cau tao thu gon cua X va Y lan luot la

1) Noone is going to the party,.....................?

A. are they      B. aren't they           C. isn't it                 D. aren't they

1) They built a new hospital near the airport last year

A. A new hospital was being built near the airport last year

B. A new hospital is built near the airport last year

C. A new hospital is being built near the airport last year 

D. A new hospital was built near the airport last year

1) Giai bat phuong trinh

a) tim m

-2 < 2-m <-1<3