Thời gian chuyển động: \(t=\dfrac{v-v_0}{a}=\dfrac{5,4\cdot10^5-5\cdot10^5}{8\cdot10^4}=0,5s\)

Quãng đường electron bay được:

\(s=\dfrac{v^2-v_0^2}{2a}=\dfrac{\left(5,4\cdot10^5\right)^2-\left(5\cdot10^5\right)^2}{2\cdot8\cdot10^4}=260000m\)

A=cos(90-x) - 2sin(180-x) + sinx

= sinx - 2sinx + sinx = 0

Ta có: \(\left(\sqrt2\cdot\sin135+\sqrt3\cdot\sin120-cos90\right)\cdot\left(3\cdot\tan135+2\cdot\cot45\right)\)

\(=\left(\sqrt2\cdot\frac{\sqrt2}{2}+\sqrt3\cdot\frac{\sqrt3}{2}-0\right)\cdot\left(3\cdot\left(-1\right)+2\cdot1\right)\)

\(=\left(\frac22+\frac32\right)\cdot\left(-3+2\right)=-\frac52\)

Ta có: \(5\cdot\sin^230^0+3\cdot cos60^0-\frac34\cdot\tan^{2022}135^0\)

\(=5\cdot\left(\frac12\right)^2+3\cdot\frac12-\frac34\cdot\left(-1\right)^{2022}\)

\(=\frac54+\frac32-\frac34=\frac24+\frac32=\frac12+\frac32=\frac42=2\)

a)Độ cao của nơi thả viên bi so với mặt đất là:

\(h=\dfrac{1}{2}gt^2=\dfrac{1}{2}\cdot9,8\cdot3^2=44,1m\)

b)Vận tốc lúc chạm đất là:

\(v=g\cdot t=9,8\cdot3=29,4m\)/s

c)Quãng đường vật rơi được (3-0,5=2,5s) trước là:

\(S_1=\dfrac{1}{2}gt^2_1=\dfrac{1}{2}\cdot9,8\cdot2,5^2=30,625m\)

Quãng đường vật rơi được trong 0,5s cuối trước khi chạm đất: 

\(\Delta S=h-S_1=44,1-30,625=13,475m\)

Environment is an essential part of our life. A clean environment is necessary for a peaceful and healthy life. An environment is the natural surroundings which helps human beings, animals and other living things to grow and develop naturally. But nowadays, our environment is disturbing in many different ways. Any type of disturbance in nature's balance affects the environment totally. It does not only ruin human lives but also affects all living beings. We can save our environment with the little step taken by everyone on the earth. We should reduce the amount of waste, throwing wastes properly to its place only and many other simple ways. It is very important to save the environment for human existence. When we protect the environment, we are protecting ourselves and our future as well.

Dear Youth Lead the Change,

I am writing to propose a project that I believe will greatly improve our community. My idea is to create a community garden in a vacant lot in our neighborhood. This garden will not only beautify the area, but it will also provide a space for community members to come together and grow their own fresh produce. This will help to address issues of food insecurity and promote healthy eating habits among our residents.

Additionally, the garden will serve as a space for educational workshops on sustainable gardening practices and environmental stewardship. It will also provide opportunities for youth to get involved in a positive and productive activity, fostering a sense of ownership and pride in their community.

I believe that this project is the best choice for our community because it addresses multiple issues, promotes community engagement, and provides valuable educational opportunities for all ages. I hope that you will consider supporting this project and helping us make our community a better place for everyone.

Sincerely, Tunn.