That is, the speed of this is (23-17) = 6m per minute, 1m per second, so the distance of 1km is 1× 1/1 = 1 seconds before meeting. Time is converted by yourself.
If we must use the equation, we can set the time to meet each other in x minutes
Then the distance that A ran should be 23x＝23x m
Similarly, B should be 16x m, and if we want to meet each other, then A will catch up with the Otsuichi circle, that is, 23x-16x = 1× 1
.
so a is definitely impossible, because the same sex repels and the opposite sex attracts. Near the North Pole, it should be N-pole downward.
on the contrary, b is right.
it is possible for the n pole near the equator to go up or down. High school math is urgent!
solution:
AC 2 = (4 sinq-3 cosq) 2+(4 cosq) 2+(3 sinq) 2
= 25-24 sinq * cosq
= 25-12 sin (2q)
Here a42 is -1, so multiply it by -1. Urgent urgent ... What is culture?
the word "culture" comes from Latin culture in the west, and its original meaning refers to farming and the cultivation of plants. Since the 15th century, it has been gradually used, and the cultivation of people's morality and ability is also called culture. In China's ancient books, "Wen" refers not only to words, articles and literary talents, but also to the system of rites and music and legal provisions. "Culture" means "education" and "teaching behavior". From the perspective of social governance, "culture" refers to educating the people with the system of rites and music.
modify the sick sentence, hurry!
① Tell you a very good news. The library has bought a new batch of children's books. I hope you can borrow them actively. In addition, every Wednesday afternoon, we will also carry out book exchange, and students can take out their books and exchange them with each other to increase the utilization rate of books. (There are five mistakes in this paragraph)
Revision:
Tell you a good news. The library has bought a new batch of children's books. I hope you can borrow them actively. In addition, every Wednesday afternoon, we will also carry out book exchange activities, and students can take out their books and exchange them with each other to improve the utilization rate of books.
remove "excellent", remove "week", move a batch to the front, add "activity" after "book exchange", and change "growth" to "improvement"
② I learned the lesson of Wuta, which made me feel a lot. I have never traveled alone, and since I went with my parents, I never cared. Compared with Uttar, I feel ashamed. I am determined that Uttar will be regarded as the object of study in the future, starting with the small things in daily life and establishing its own independent ability. (There are seven mistakes in this paragraph)
Revision:
After learning the lesson Wuta, I have a lot of feelings. I have never traveled alone, and even if I go with my parents, I have never cared. Compared with Uttar, I feel very ashamed. I am determined to take Uttar as the object of study in the future, starting with the little things in daily life and exercising my independent ability.
remove make; Get rid of isolation; Since it is changed to even; Remove feelings and add feelings; Remove and add; It is urgent to set up and change to exercise in the first year of high school!
1. Main contents of the New Deal:
Reviving the economy, relieving and resettling the unemployed and refugees, and getting rid of some disadvantages of monopoly capitalism.
characteristics: the state has stepped up its intervention in the economy.
Function: (economically) the American economy has gradually stepped out of the trough. (politically) eased class contradictions and prevented the United States from embarking on the road of French dictatorship due to the economic crisis.
3. Farmers' dissatisfaction and natural disasters have led to peasant riots, which have further affected workers' production and life.
implement single public ownership; Implement a high degree of economic management system and manage the economy by means of administrative orders;
planned economy, denying the market and establishing an independent economic system.
Everything should proceed from reality
Adjustment of production relations should adjust productivity
Coordinated development of economic construction
Combination of economy and market two economic systems is urgent!
The high jump is one of the field events. The pole-crossing techniques include leaping, scissors (also known as "eastern style"), rolling, prone and back-crossing. The high jump originated in Britain and was derived from gymnastics. In 1864, Britain first included the high jump in the field events. The Englishman Kenai jumped over 1.7 meters by leaps (the most primitive and simple high jump posture). Men's jumping was listed as an official event at the first Olympic Games in 1896. Women's jumping was officially included in the Olympic Games in 1928. Scissor high jump originated in America. At the end of the 19th century, athletes in the eastern states of the United States created and adopted this high jump posture, so it was once called the "oriental style". It is also called "wave type" because all parts of the body jump in a wave shape and cross the crossbar in turn. The roll high jump also originated in America. At the beginning of the 2th century, American athletes in the western states created and adopted the roll high jump, which was named after the athlete's appearance of rolling over a crossbar when jumping. It is also called "Horatio English" because American athlete Horatio first set a world record of 2.1m with this formula. The prone high jump started in the 192s and was widely adopted in the 194s. At present, the most popular high jump is the fosbury flop, while several other high jump styles have almost disappeared in competitions.
The high jump originated from the activities of ancient human beings crossing vertical obstacles in life and labor. The modern high jump began in Europe. There was a high jump competition in Scotland at the end of 18th century, and it became popular in Europe and America in 196s. On September 26th, 1827, in the first professional track and field competition held in Saint Laurent Boadle Club, England, Adam Wilson jumped 1.575 meters on his knees, which was the first recorded high jump in the world. There are some techniques in high jump, such as leaping, scissors, prone and fosbury flop, and now most athletes adopt fosbury flop. The high jump crossbar can be made of fiberglass, metal or other suitable materials, with a length of 3.98~4.2 meters and a maximum weight of 2 kg. During the competition, athletes must take off with one foot, and can try to jump at any specified jumping height, but there are only three attempts at the first height. The men's and women's high jump were listed as Olympic events in 1896 and 1928 respectively.
The high jump has many benefits for human body!
Physiologically:
1. Physical exercise is beneficial to the growth of human bones and muscles, enhancing cardiopulmonary function, improving the functional status of blood circulation system, respiratory system and digestive system, promoting human growth and development, improving disease resistance and enhancing the adaptability of organisms.
2. Reduce the chances of children suffering from heart disease, hypertension, diabetes and other diseases in adulthood.
3. Physical exercise is one of the most active and effective means to enhance physical fitness.
4. It can reduce your risk of premature aging.
5. Physical exercise can improve the regulation function of the nervous system, improve the ability of the nervous system to judge the complicated changes in human activities, and make a coordinated, accurate and rapid response in time; Make the human body adapt to the changes of internal and external environment and keep the normal life activities of the human body.
Psychologically:
1. Physical exercise has the function of regulating human tension, improving physical and psychological state and restoring physical strength and energy;
2. Physical exercise can improve physical health, make the tired body have a positive rest, and make people energetically engage in study and work;
3. Stretching your body and mind can help you sleep well and eliminate the pressure brought by reading
4. Physical exercise can cultivate your sentiment, maintain a healthy mentality, and give full play to your individual's enthusiasm, creativity and initiative, so as to improve your self-confidence and values and make your personality develop healthily and harmoniously in a harmonious atmosphere;
5. Group events and competitions in physical exercise can cultivate people's spirit of unity, cooperation and collectivism.
Teenagers are an important turning point in people's life when their physical and mental development tends to be mature. At this time, you will be surprised to find that there are many unprecedented changes in physiology and psychology, and obviously feel that I have grown up. With the improvement of people's living standards and cultural quality, "everyone has the heart of beauty", so we should thrive in sports and keep fit in sports.
Therefore, high jump is not only a sport, but also a fitness exercise.
Here, I appeal to everyone to take part in the high jump for the development of sports and their own healthy growth! Please, everyone, hurry!
"Yu Gong Yi Shan" is not a true story, but it is a household name in China. This story is recorded in Liezi. Liezi is a book written by a philosopher named Lieyukou in the 4th and 5th centuries BC.
According to the story, there was an old man named Yugong, who was almost ninety years old. There are two mountains in front of his house, one is Taihang Mountain, and the other is Wangwu Mountain. It is very inconvenient for people to go in and out.
One day, Yu Gong called the whole family together and said, "These two big mountains are blocking the door of our house, so we have to take many wrong roads to go out. Why don't we help the whole family to move these two mountains? " .
Hearing this, Yugong's sons and grandchildren all said, "You're right, let's start tomorrow. ！” However, Yugong's wife thought it was too difficult to move two big mountains, and raised an objection, saying, "Since we have lived here for many years, why can't we go on living like this?" Besides, even if these two big mountains can be removed a little, where can so many stones and mud be put? "
The words of the foolish old man's wife immediately aroused everyone's discussion, which is really a problem. Finally, they unanimously decided to transport the stones and mud from the mountains to the sea.
The next day, Yugong and his family started moving mountains. His neighbor is a widow. She has a son who is only seven or eight years old. When she heard that she was going to move the mountain, she also came to help happily. However, the only tools for the Yugong family to move mountains are hoes and baskets, and the mountains are far away from the sea, so one person can't go back and forth twice a day. After a month's work, the mountain looks the same as before.
There was an old man named Zhisou, who was very shrewd in dealing with people. He felt very ridiculous when he saw the Yugong family moving mountains. One day, he said to Yu Gong, "You are so old that it is not convenient to walk. How can you move two big mountains?"
Yu Gong replied, "Your name is Zhizuo, but I don't think you are as clever as a child. Although I am going to die, I still have a son. My son is dead, and there are grandchildren, children and grandchildren, which have been passed down endlessly. The stone on the mountain is a little less when it is removed, and no mud or stone will grow again. We move every day, every month and every year. Why can't we move the mountains? " The wise old man, who thinks he is clever, has nothing to say anymore.
Yu Gong leads his family, no matter whether it is hot summer or cold winter, they get up early and dig mountains in the dark. Their behavior finally touched God. So God sent two immortals to earth and moved the two mountains away. But the story of Yugong moving mountains has been passed down to this day. It tells people that no matter what difficult things are, as long as they are persevering, they may succeed. Physics problem of grade 3. Urgent ~ `!
W=F*S F=G shoes S= calculate how many times shoes are lifted by an h = total distance/distance between two forest feet.