How to calculate the horizontal friction in high school
I. calculation of sliding friction
1= μ FN calculation.
(1) according to the force condition of the object, calculate the positive pressure FN.
(2) according to the formula F= μ 2. Two force balance method: the object is in the state of equilibrium (uniform velocity, static positive), according to the two force balance conditions to solve; 2、 Calculation of static friction force
1. Balance condition method is used to solve static friction force. As shown in Fig. 3-3-19, a static object is placed on the horizontal plane. When a person pushes the object with horizontal thrust, the object is still. According to the two force balance condition, the static friction force is equal to the thrust force,
2, The value range of static friction is O & lt; F ≤ Fmax is independent of the positive pressure between objects, so the formula F cannot be used= μ FN solution.
3. Maximum static friction Fmax The value is equal to the external force along the contact surface when the object is just sliding, which is the maximum value of static friction and greater than sliding friction. Generally speaking, they are equal, and the maximum static friction is Fmax.. The formula is Fmax= μ Static FN, μ Static is the static friction coefficient and specific dynamic friction coefficient between objects μ Slightly larger
Object B is relatively static with a, so it is subject to static friction here (it is impossible not to be subject to friction force, because there is a relative motion trend between ab). Set f
because ab is relatively static, the acceleration of both is the same, and because it is relatively static, it can be regarded as the same object, and the acceleration A1 = GSIN θ-μ 2gcos θ
now let's look at ab separately. The acceleration of B is A2 = A1 = (mgsin θ- f)/m=gsin θ-μ 2gcos θ,
we can get F= μ 2mgcos θ
please go straight, enter the outer ring expressway, drive 14.1 km
drive to the front right, enter the Xinzhuang overpass, drive 1.3 km
please go straight, enter the Hujin expressway, Drive 2.9km
keep right ahead, from Hujin Expressway to Jin Road, drive 540M
turn left, enter Jin Road, drive 760m
turn left, enter old humin Road, drive 870m
turn right, from old humin road to naierbao Family Center (Xinghewan store)
What's my answer?
I don't have time to take my baby to work at ordinary times. I have time on weekends, so I can just go for a stroll. Today I recommend some interesting places that can't be exposed to the sun. If I have nothing to do on weekends, I can consider taking my baby for a stroll ~
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fire station, simulation fire water truck with children's fun water gun, it's like coming to the fire scene in person, and the children are unwilling to go when they play; Ar racing is really a way to restore the racing conditions of the racetrack. The real scene is synchronized with the screen. Boys like it so much ~ Holland club takes the baby to experience the extremely realistic racing tide experience
meland club enables every child to become an artist, play in middle school, play in learning, teach in fun, and take children for a walk in the weekend ~
address: meland club, 3rd floor, Vientiane world, 9668 Shennan Avenue, Shenzhen City
subway: exit a of gaoxinyuan station, Just pick one. It's fun and can't be exposed to the sun. It's also good for children's knowledge
prepaid cards are commonly used in service-oriented instries with strong user stickiness, such as beauty salons, fitness clubs, restaurants and hotels. Many citizens have had similar experience in card purchasing. Originally prepaid card should be a win-win card, businesses can stabilize users, consumers can also enjoy discounts. However, in practice, financial risks and consumer disputes are constantly emerging. Therefore, the Ministry of Commerce of the people's Republic of China has issued special regulations to regulate and manage the issuance of prepaid cards by enterprises. The supervision has achieved certain results, but it does not seem to achieve the expected results. A few days ago, Jiangsu TV reporters visited Nanjing, Huai'an and other places and found many problems
to purchase a registered card, you need to register your ID card merchant: mobile phone number! On November 7, the reporter made a random visit to a number of shops in Nanjing, such as beauty salons, children's entertainment, restaurants and hotels, and found that many businesses still had many irregularities in handling prepaid card business. According to the relevant regulations of the Ministry of Commerce, if an indivial or unit purchases a registered card, or purchases an anonymous card of more than 10000 yuan at one time, the card selling enterprise shall require the card buyer to proce a valid identity card. In the actual experience, the reporter found that only one restaurant required to register ID card
to purchase a registered card, you need to register your ID card merchant: mobile phone number! Reporter investigation found more chaos
staff of Nanjing Huacai Tiandi store of naierbao Family Center: no need to register the customer's ID card, just need the baby's photo and parents' mobile phone number, because it is through the mobile phone number to get out the bracelet<
staff of Nanjing Wanda Plaza store of pineapple tree inspirational toy experience Museum: you don't need the customer's ID card, you just need the phone number to get the card, and it's also an electronic card
[a single registered card shall not have a period of validity, and some businesses skillfully use annual cards to set a period of validity]
according to relevant regulations, registered cards shall not have a period of validity; The validity period of anonymous card shall not be less than 3 years. The reporter found that the nairbao family center did not comply with this
to purchase a registered card, you need to register your ID card merchant: mobile phone number! Reporter investigation found more chaos
staff of Nanjing Huacai Tiandi store of naierbao Family Center: the annual card is valid for one year, and it is OK for customers to come 5 times, 10 times and 100 times in a year. The second time card is 15 times and valid for one year; The validity period of the 10 times card is half a year< In addition, according to relevant regulations, the limit of a single registered card shall not exceed 5000 yuan, and the limit of a single anonymous card shall not exceed 1000 yuan. However, in the interview, the reporter found that two hair salons and three restaurants were beyond the limit, and even said there was no upper limit
to purchase a registered card, you need to register your ID card merchant: mobile phone number! The reporter's investigation found more chaos
staff of Batu modeling Wanda Plaza store in Nanjing: for a 10000 yuan hairdressing card, you can enjoy a 50% discount
to purchase a registered card, you need to register your ID card merchant: mobile phone number! The reporter's investigation found more chaos
staff of huoqilin huacaitiandi branch in Nanjing: the maximum recharge is 10000 yuan or 20000 yuan
to purchase a registered card, you need to register your ID card merchant: mobile phone number! The reporter's investigation found more chaos
the staff of Huacai Tiandi branch of lion palace in Nanjing: recharge 5000 yuan to get 1000 yuan, flush 10000 yuan to get 2000 yuan, and there is no upper limit<
["the period of estoppel" shall be ignored, and the merchant clearly states that the card will not be returned]
according to the relevant provisions of the regulations of Jiangsu Province on the protection of consumers' rights and interests, the consumer has the right to ask for a refund without reason within 15 days from the date of payment. However, in the process of visiting Nanjing and Huai'an, when the reporter mentioned whether he could go back on his card, he was rejected by the merchants.
The kingdom of nairbao covers an area of 5000 square meters, and the luxurious European architecture can not hide its pink maiden heart. The whole park is divided into five areas: library, restaurant, climbing Kingdom, mock city and party world. It's not enough to spend a whole day in it. 1. Forest Library: the rolling hills are well arranged. On the hills are displayed more than 20000 selected original English books, ranging from baby's hole books to best-selling books enjoyed by urban people. The fragrance of books ferments in the forest of fairy tales, which is a miniature version of sincere fairy tales. Inside the Elf tree hole is the children's whimsical secret space. Our children are born to belong to nature. In this comfortable and quiet forest kingdom, we spend half a day soaking in books to take our children to explore the unknown world. 2. Hot air balloon restaurant: on the edge of the ancient wall built by nairbao, the sparkling lake water is rippling. Here, children carry colorful hot air balloons to fly to the distant universe and explore the unknown world. The transparent glass reinforced tunnel is connected with five hot-air balloons. Children can slow down and explore one by one. The parents sitting around stop for a while, have a cup of afternoon tea, take photos, and watch the children's play 360 degrees. 3. Improper children's stair slide: all the children who follow the rules seem to be imperfect childhood. The children's slide beside the forest library explains what it means: walking is not serious! Next to the stairs leading to the second floor, there is a fast slide for a group of children who don't like to be serious. They get into the slide and rush into the ocean ball pool. Then they look back at their parents standing on the stairs and show off their "super speed". The warm parents and children are immediately moved. 4. The simulation city in children's country: the 10 meter high-rise simulation city leads children into a city of the future. The complete highway system, cars running around the small city, the simulation of walking, watching the traffic lights on the side of the road, reminds children to abide by the order, super real. The first floor of the city provides the necessary facilities for daily life, such as supermarkets, banks and gas stations. It is worth mentioning that banks can really insert cards and dryers can really open the lid. Isn't it cool? On the second floor of children's country, children work here and experience different professional lives. Doctors, police, cooks and couriers can play whatever they like. Let the children decide their own world. 5. Princess Castle: the secret castle of the girls, in which we quietly become beautiful. Please choose your favorite manicure style first. You can come to the barber's desk and choose your favorite animal modeling car. You can wait for the barber to take care of your hair comfortably. From the revolving stairs to the princess dressing room, the princess dress in the display window will be a blessing for your princess. There is also an exclusive make-up artist to serve you one-on-one. 6. Physical exploration: stimulate the unlimited potential of little tough guys. If the whole naierbao is too young for boys to play, it will miss half the world. The eight meter high climbing frame is waiting for the tough guys to challenge. The intricate climbing net absolutely challenges physical potential and tests children's adaptability. Finger pressure plate slide has become a new favorite. Smooth slide can slide. How can small bumps like finger pressure plate be made into slide? This is the only finger pressure board slide in Shanghai. The slope is not high, and the process is very cool. Put on a rubber ball pad and slide down from a high place. Listen to the wind whirring in your ears, and feel the creaking acidity of PP, which is worth experiencing. 7. The dream starry sky party in the deepest part of the castle: you've seen too many luxurious party rooms in Mordor. You must not have attended the Party of turning off the lights to enjoy the starry sky. Urban children look up only to see street lights, how many children have never seen the starry sky flashing? In addition to the starry sky party room, there are Indian style, Turkish Mediterranean style and desert style party rooms. Even if you see more theme rooms, you will scream for them. 8. Turkey's dream Ocean: with waves as the ground and shells as the top, listening to the chime playing by the blue pool, fingertips skimming over the water like a mother's touch. Next to the party room on the ground floor, a turkey's dream ocean is waiting for the arrival of children. Children who are born to love water are here to explore the mysteries of water, such as water piano, water ball, water pipe, and explore the infinite possibilities in water with limited props
you can also see more about the introction and play of nairbao Family Center (Star River store) and the surrounding scenic spots on flying pig
1. Shanghai World
Shanghai world is a famous amusement center in Shanghai. It is composed of four parts, namely "Amusement World", "Expo World", "competitive world" and "food world", with eight series of amusement projects. In the early 1990s, the "big world challenge arena" and the "Guinness record challenge arena" in the "competitive world" competition attracted unique experts from all over the country and created many "unique" and "first" records in the world and China. The strong Shanghai style cultural color and the entertainment facilities pursuing the flavor of the times attract thousands of guests at home and abroad
Shanghai Happy Valley is located in Songjiang Sheshan National Tourist Resort in the southwest of Shanghai, 40 kilometers away from the downtown area of Shanghai, 25 kilometers away from Hongqiao International Airport and 68 kilometers away from Pudong International Airport. Shanghai Happy Valley covers an area of 650000 square meters and has more than 100 experience projects. There are seven theme areas in Shanghai Happy Valley: sunshine harbor, happy time, Shanghai beach, Shangri La, happy ocean, gold town and hurricane Bayin May 2012, Shanghai Happy Valley was rated as "national AAAA tourist attraction"; From 2012 to 2016, Shanghai Happy Valley won the most popular scenic spot of the year of "winning the tourism instry award" for five consecutive years
3. Shanghai old amusement park
Jinjiang Amusement Park, an old Shanghai amusement park, has also opened its night show, which has attracted many visitors. It is reported that the night show of the park will be open from July 13 to August 25. During the night show, the park will be open to 22 o'clock every night. More than 30 entertainment facilities, such as giant Ferris wheel, magic windmill, rolling waves, giant suspended roller coaster, will welcome tourists at the night show
Jinjiang park is the first large-scale modern amusement park in Shanghai, China, covering an area of 170 mu, with a total of 40 amusement projects, suitable for tourists of all ages, receiving about 1 million tourists every year