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29 tháng 4 2018

Do you believe that flying cars have appeared 70 years ago? Since writer Jules Verne introduced the idea of flying cars in the novel Master of the World, published in 1904, generations of engineers have been trying to make flying cars. In 1940, Henry Ford (founder of Ford Motor Company) predicted that the combination of aircraft and cars would occur at a time when both low cost and cheaper aircraft and cars were mass use. The combination of these two vehicles is inevitable. Ford's prediction proved to be true. Only a few years later, an aeronautical engineer named Ted Hall launched the first fully functional flying car.

29 tháng 4 2018

dịch thành tiếng việt zúp mk đc k ạ

16 tháng 5 2017

In the future, there will be high-speed train. The train will go around the city. It’s driverless train. It will use electric and solar-powered. It will look like an airplane without wings. It will help people to travel faster and safer.

>> Tham khảo ạk <<

9 tháng 4 2017

Everybody loves holidays because during out holidays we can relax and have fun. We get enough time to travel, play our favourite sports and practive our hobbies. My favourite is holiday. Below I will tell you about my holiday. I will so many activity which includ swimming, football,..... We will go on vacation in Ha Long bay. There are lots of fresh and delicious seafood. My holiday forch exciting and fun of joy. I engjoy it immensely. I am looking forward to going there again soon

23 tháng 3 2018

It is Solar-energy plane. It looks a normal plane but it has the solar panel on the wings. The panel will catch the sun shine and create the electricity for the plane. It maybe a great invention helping to create the energy and protect environment.

Nó là máy bay năng lượng mặt trời. Nó trông như máy bay thông thường nhưng nó có tấm pin mặt trời trên cánh. Tấm pin sẽ nhận ánh nắng mặt trời và tạo ra nguồn điện cho máy bay. Nó có lẽ là một phát minh lớn giúp tạo ra năng lượng và bảo vệ môi trường.

 Nhớ k nha !

9 tháng 4 2018

In the future, I think people won't be worried about travelling because of teleporters.It will look a big magic box or maybe it will be designed as a magic lift.In my opinion, it will be powered by solar energy and it will combine the function of a 3D map. Just think about going into a teleporter in France and choosing Vietnam as the destination. Then, 3 minutes later, you will be in Hanoi - Vietnam. That will be great.People can use it anytime and anywhere. It won't take a lot of space.I think it will replace all other vehicles and it will make people around the world closer.

9 tháng 4 2018

I think in the future, most people will travel by flying cars.I think that it will have 2 wings so that it can fly as a plane. It will not be as big as the plane, but its speed will be higher than any other vehicles now.I think flying cars will use solar power with super thin batteries and they will use the technology called Vehicle-to-Vehicle communication, or V2V, which means cars will communicate with each other to avoid crashing. A flying car will be used for air transport, but it can also be used on the road. People can control it by touching on the control panel or they can set it in the automated control system. It can be used both in the city and in the countryside.I think flying cars will be one of the most popular means of transport in the future because they are environmentally friendly and we can avoid traffic jams by using them. However, I think we may need a sky safety system to avoid crashing.I think flying cars will be one of the most popular means of transport in the future because they are environmentally friendly and we can avoid traffic jams by using them. However, I think we may need a sky safety system to avoid crashing.

18 tháng 4 2022

bạn Vy đẹp trai gì đó ơi

I'm really sorry

I don't know English

có nhất thiết phải nói thế ko:)?

29 tháng 5 2016

Gọi vận tốc ô tô ban đầu là x (đk  x>0)   (km/h) 

thời gian đi nửa quãng đường còn lại với vận tốc ban đấu là :\(\frac{420}{x}\)(giờ)

thời gian đi nửa quãng đường còn lại là :\(\frac{420}{x+2}\)(giờ)

Vì đi được nửa quảng đường xe nghỉ 30 phút nhưng vẫn đến B đúng giờ ,ta có pt:

\(\Rightarrow\)\(\frac{420}{x+2}+\frac{1}{2}=\frac{420}{x}\)

\(\Rightarrow\)\(840x+x\left(x+2\right)-840\left(x+2\right)=0\)

\(\Leftrightarrow\)\(x^2+2x-1680=0\)

\(\Rightarrow\)\(x1=40\left(nhận\right)\)và \(x2=-42\left(loại\right)\)

\(Vậy\)vận tốc ban đấu của ô tô là 40 km/h

26 tháng 11 2016

Gọi thời gian máy bay, ô tô, xe lửa đi hết quãng đường AB lần lượt là a; b; c (km; a;b;c > 0)

Theo bài ra ta có: b - a = 6

Vì quãng đường đi như nhau nên thời gian và vận tốc là 2 đại lượng tỉ lệ nghịch

=> 6a = 2b = c

\(=\frac{a}{\frac{1}{6}}=\frac{b}{\frac{1}{2}}=c\)

Áp dụng tính chất của dãy tỉ số = nhau ta có:

\(\frac{a}{\frac{1}{6}}=\frac{b}{\frac{1}{2}}=c=\frac{b-a}{\frac{1}{2}-\frac{1}{6}}=\frac{6}{\frac{1}{3}}=6.3=18\)

=> b = 18.\(\frac{1}{2}=9\)

Vậy thời gian ô tô đi hết quãng đường AB là 9h