a) \(S_1=d_1=50\left(m\right),t_1=40\left(s\right)\)

\(=>v_{tb\left(1\right)}=v_1=\dfrac{S_1}{t_1}=\dfrac{50}{40}=1,25\left(m/s\right)\)

b) \(S_2=d_2=50\left(m\right),t_2=42\left(s\right)\)

\(=>v_{tb\left(2\right)}=v_2=\dfrac{S_2}{t_2}=\dfrac{50}{42}=\dfrac{25}{21}\left(m/s\right)\)

c) \(S_3=S_1+S_2=50+50=100\left(m\right),d_3=0\left(m\right)\\ t_3=t_1+t_2=40+42=82\left(s\right)\)

\(=>v_{tb\left(3\right)}=\dfrac{S_3}{t_3}=\dfrac{100}{82}=\dfrac{50}{41}\left(m/s\right)\)

\(v_3=\dfrac{d_3}{t_3}=\dfrac{0}{82}=0\left(m/s\right)\)

Tốc độ trung bình tính theo công thức:

$v_{\mathrm{tb}}=\frac{\mathrm{Quãng}\mathrm{đường}\mathrm{đi}\mathrm{được}}{\mathrm{Thời}\mathrm{gian}\mathrm{đi}\mathrm{quãng}\mathrm{đường}\mathrm{đó}}=\frac{s}{t}$

Lần đi: v1 = 50/40 = 1,25 (m/s)

Lần về: v2 = 50/42 = 1,19 (m/s) 

Cả đi và về: 

$v_3=\frac{2.50}{40+42}=1,22(m/s)\Rightarrow v_1+v_2+2v_3=4,88(m/s)$

1. Yes, I have given money to charity on several occasions
2. I can help people in my community by volunteering my time, participating in community projects, and supporting local initiatives
3. Yes, I would like to be a member of an international organization to contribute to global causes and make a positive impact on a larger scale
4. Some benefits of volunteering activities include personal fulfillment, skill development, building a sense of community, and making a positive impact on others' live
5. No, there are no different rules for boys and girls at my school. Everyone is treated equally
6. No, I don't believe there are jobs that only men can do. Gender should not limit one's career choices, and everyone should have equal opportunities based on their abilities and qualifications

Vì chất này có thể kích thích các tế bào niêm mạc tiết ra dịch nhầy làm cho thức ăn di chuyển dễ dàng trong đường ruột đảm bảo quá trình tiêu hoá thức ăn diễn ra thuận lợi và hiệu quả.

Việc đổ ngập nước và đậy kín ngăn cho khí O₂ không vào trong được, quá trình hô hấp của các VSV không diễn ra hoặc gặp bất lợi => Quá trình lên men mới được diễn ra

because it in ezzzzz

1 We provided support for Nepal after the earthquake in 2015

2 Jane Austen started writting her first novel when she was 20

Question 1: Mrs. Kim didn't let Lucy adopt a pet until she was ten. (allow)

Mrs Kim didn't allow Lucy to adopt a pet until she was ten

Question 2: How long has Sam been attending art classes? (When)

When did San attend art classes?

Question 3: “Are you nervous about your upcoming job interview?” Tom asked me. (if) (Use reported speech)  

Tom asked me if I was nervous about my upcoming job interview