Một hòn bi có khối lượng 100g được ném thẳng lên từ độ cao 10 m với vận tốc 10m/s, lấy g = 10m/s². Chọn gốc thế năng tại mặt đất, bỏ qua ma sát của không khí.

a. Tính trong hệ quy chiếu mặt đất các giá trị động năng, thế năng và cơ năng của hòn bi tại lúc ném vật.

b. Tìm độ cao cực đại mà vật đạt được so với mặt đất.

c.  Ở vị trí nào của vật thì W_đ = 3W_t.

d. Xác định vận tốc của vật trước khi chạm đất.

e. Chịu lực cản 10N thì độ cao mà hòn bi đạt được là bao nhiêu?

In the age of technology, laptop is used widely. The laptop brings us a lot of benefits for our live. it is very versatile as it can do many things. firstly, it is portable. therefore, people can take it everywhere. secondly, it is economical so everyone don't have to spend too much money to buy it. besides, the laptop is a mean of entertainment. we can use it to listen to music, to chat with friends, to make video call with parents, to play games, and so on. last but not least, we can use laptop for studying. for example, the laptop can be used for researching topics on the Web or typing the assignment as well. In summary, laptop is definitely one of the greatest inventions in the world as well as the best thing in our society.

Mozart, who was born on January 27, 1756 in the Austrian city of Salzburg, was neither the first nor the last child prodigy, but he was certainly the greatest. He was born into a moderately prosperous family where his unmatched musical genius made itself known extremely early. Mozart began learning to play the harpsichord at three and his earliest known work was composed in 1761 when he was five, the age at which he also first appeared in p ublic. From the age of six, his father took him on the first foreign tour, Mozart toured the courts and musical centres of Austria, Germany, France, England, Holland, Switzerland and Italy. It has been calculated that Mozart spent almost a third of his short life ( he died at the age of 35) travelling. As Mozart matured, he continued to tour and give concerts. Mozart also wrote a lot of operas. His first opera, Mitridate, Re di Ponto, was performed in Milan when he was 14, and it was one of many successes in the life of the genius.

In the age of technology, laptop is used widely. The laptop brings us a lot of benefits for our live. it is very versatile as it can do many things. firstly, it is portable. therefore, people can take it everywhere. secondly, it is economical so everyone don't have to spend too much money to buy it. besides, the laptop is a mean of entertainment. we can use it to listen to music, to chat with friends, to make video call with parents, to play games, and so on. last but not least, we can use laptop for studying. for example, the laptop can be used for researching topics on the Web or typing the assignment as well. In summary, laptop is definitely one of the greatest inventions in the world as well as the best thing in our society.

P/s: Mình nghĩ nói ngắn quá sẽ không có điểm cao lắm đâu, không cần nói quá dài hoặc quá ngắn. Chỉ cần đầy đủ ý trong bài là ok. Với lại khi nói bạn nhớ phải tự tin lên nha. FIGHTING!!!!

The health is very important with our life. If you haven't got a good health, you won't have perfect happiness in your life. So it's necessary to keep fit and stay healthy. There are hundreds of thousands of way to keep your fit. First, you should morning exercises or play sport as ride bike in fresh air. Second, you should have a good diet, eat enough nutriment. Always have breakfast. And you should have meal in time. The best time to have lunch is about 11 am to 12 am and for dinner is about 6 to 7 pm. You should eat less meat, especial beef, turkey, pork, etc. And should eat a lot of fruit and vegetable; should drink lots of water, about 1 liter to 2 liter per day. Besides, you should take part in some outdoor activities such as playing sports. It helps you reduce stress and gain energy after working hard. You should have sufficient sleep, at least 6 hours per day. Finally, you should see the doctor regulary periodic examine. Moreover, spending time with family and friends maybe improve your mental health so you are happier and healthier.

In the age of technology, laptop used widely. The laptop brings us a lot of benefits for our live. It is very versatile as it can do many things. Firstly, it is portable. Therefore, people can take it everywhere. Secondly, it is economical so everyone don't have to spend to much money to buy it. Besides, the laptop is a mean of entertainment. We can use it to listen to music, to chat with friends, to make video call with parents, to play games, etc. Moreover, we can use laptop for studying. For example, the laptop can be used for researching topics on the Website or typing the assignments as well. In short, laptop is one of the greatest inventions in the world as well as the best thing in our society.

đổi 25% = 1/4 

ta có sơ đồ 

con 1 phần 

mẹ 4 phần 

tuổi con là 

26 : 4 = ..

không tìm được tuổi con

thôi tao biết viết rồi thằng ngu Roronoa Zoro

\(-4-7.\left(x-2\right)=-32\)

    \(-4-7x+14=-32\)

            \(-7x+10=-32\)

                       \(-7x=-32-10\)

                       \(-7x=-42\)

                             \(x=\left(-42\right):\left(-7\right)\)

                             \(x=6\)

Vậy \(x=6\)

biết biết kiểu viết ở ngoài giấy không mà còn chửi người ta là ngu mày giống tao thôi

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