Question 1: What types of pulleys are there and what are their functions? Ping An designs insurance [Hongyun Yingcai] insurance for children’s expensive education expenses, including education fund/entrepreneurship fund/marriage fund/dividends/with accidental medical treatment; Ping An designs insurance specifically for children aged 28 days to 10 years old, with earmarked funds to reserve future protection in advance so that children can have a wonderful life.
Question 2: What are the benefits of roller skating 1. Adjusting the amount of exercise can achieve various effects, such as weight loss, etc.
- Burning 570 to 1150 calories per hour is as effective as running
- Generally speaking, the maximum oxygen consumption of roller skating (the benchmark for measuring exercise intensity) is running of 90, which is very effective in maintaining the optimal intensity of aerobic exercise.
- According to research, the heart rate measured when roller skating at a speed of 23km/hr is 74 of the maximum heart rate. This is a typical aerobic exercise that can achieve the effects of strengthening the cardiovascular system and burning fat.
- Accelerate the speed to 28km/hr, and the heart rate will reach 85 of the maximum heart rate and exceed the anaerobic threshold. At this time, the endurance of the muscles can be improved.
- By continuously roller skating, you can adjust your body to the best condition.
2. Low risk of injury
- Because roller skating is different from running, the wheels rotate when the roller skating steps. The elasticity of the wheels made of polyurethane has little impact on the joints, so the elderly are also suitable for this activity. Sports - Wear a helmet and protective gear, the risk of injury after falling is very small
3. It is a very good exercise for children in the growing period
- Improves the sense of balance, movement, physical strength, endurance, etc. to help the growth and development of children during the growing period
- In Exercising outdoors with more people can make your personality more cheerful
- It has the effect of burning fat and can prevent the symptoms of obesity in children
4. Exercises to do with the family
- From growing children to the elderly, men, women and children can enjoy exercise together
- Exercises that are easy to learn
- It is also easy for women to learn. In fact, the male to female ratio of roller skaters is 50:50
5. Economical sports
- If you buy good equipment when you are a beginner, you will almost never have to spend anything else
- Unlike swimming, tennis and other sports, roller skating does not require a specific place and does not cost as much as entering. Money from field tickets
- can be used as a means of transportation according to your own strength
6. You can make more friends through roller skating
- Contact more people by participating in clubs and other activities and you will make many friends
- You can roller skate alone, and it is more beneficial to roller skate with multiple people Interest
7. It’s not easy to get bored
- Roller skating can be used in various sports such as leisure, speed skating, street racing, freestyle, roller skating, and tricks, so it’s not easy to get bored
- Look at yourself You will feel a sense of accomplishment with the development of roller skating technology
8. When reaching a certain technical level, extra points will be added in the college entrance examination
- Candidates who have won the title of national second-level athlete or above and have been tested and recognized by the provincial admissions committee in the year of application. The score can be appropriately increased based on the total score of the candidate's unified examination
Question 3: What are the benefits of using a pulley
The pulley is composed of a grooved disc that can rotate around a central axis and A simple machine composed of a flexible cable (rope, tape, steel cable, chain, etc.) that spans the disk and can rotate around a central axis. The pulley is a deformation of the lever and belongs to the simple lever type machine. In our country, there are records about pulleys in the book "Mo Jing" as early as the Warring States Period.
The pulley with a fixed central axis is called a fixed pulley. It is a deformed equal-arm lever that does not save effort but can change the direction of the force. The pulley whose central axis moves together with the weight is called a movable pulley. It is a deformed unequal arm lever that can save half the force but does not change the direction of the force. In practice, a certain number of movable pulleys and fixed pulleys are often combined into various forms of pulley blocks. The pulley block saves effort and can change the direction of force.
The differential pulley (commonly known as a hand chain hoist) commonly used in factories is also a pulley block. Pulley blocks are widely used in cranes, hoists, lifts and other machinery.
There are two types of pulleys: fixed pulleys and movable pulleys
(1) Fixed pulleys are essentially equal-arm levers, which are effortless and effortless, but can change the direction of the force.
Characteristics of the fixed pulley
It is not labor-saving to use the fixed pulley to pull the hook code. The reading of the spring balance is the same with or without the fixed pulley. It can be seen that using a fixed pulley does not save effort but can change the direction of the force. In many cases, changing the direction of the force will bring convenience to the work.
The principle of the fixed pulley
The fixed pulley is essentially an equal-arm lever. The power L1 and resistance L2 arms are equal to the radius of the pulley. According to the lever balance condition, it can also be concluded that the fixed pulley is not labor-saving.
(2) The moving pulley is essentially a lever whose power arm is twice the resistance arm, saving 1/2 the effort and spending 1 times the distance.
Characteristics of the moving pulley
Using a movable pulley can save half the effort and waste distance. This is because when using a movable pulley, the hook code is hung by two sections of rope, and each section of rope only bears half of the weight of the hook code. Although using the movable pulley saves effort, the distance moved by the power is greater than the distance the hook code is raised, that is, the distance is wasted.
The principle of the movable pulley
The movable pulley is essentially a lever whose power arm (L1) is twice the resistance arm (L2).
(3) Pulley block: A pulley block composed of a fixed pulley and a movable pulley, which saves labor and can change the direction of the force.
The pulley block uses several lengths of rope to hang the object and lift the object. The force is a fraction of the total weight. The free end of the rope that goes around the movable pulley is counted as a section, but the one that goes around the fixed pulley is not counted.
Although using a pulley block saves effort, it costs a lot of distance. , the distance moved by the power is greater than the distance moved by the heavy object.
Purpose of the pulley block:
In order to save money and change the direction of the power, the fixed pulley and the movable pulley can be combined into a pulley block.
Effort-saving
When using a pulley block, the pulley block uses several lengths of rope to hang the object, and the force used to lift the object is only a fraction of the weight of the object.
Characteristics of the pulley block
By experimenting with the pulley block, it is easy to see that although using the pulley block saves effort, it costs distance - the distance moved by power is greater than the distance of the cargo. .
A simple machine that can rotate around a central axis, consisting of a grooved disc that can rotate around a central axis and a flexible cable (rope, tape, steel cable, chain, etc.) that spans the disc. . The pulley is a deformation of the lever and belongs to the simple lever type machine. In our country, there are records about pulleys in the book "Mo Jing" as early as the Warring States Period. The pulley with a fixed central axis is called a fixed pulley, which is a deformed equal-arm lever that does not save effort but can change the direction of the force. The pulley whose central axis moves together with the weight is called a movable pulley. It is a deformed unequal arm lever that can save half the force but does not change the direction of the force. In practice, a certain number of movable pulleys and fixed pulleys are often combined into various forms of pulley blocks. The pulley block saves effort and can change the direction of force.
The differential pulley (commonly known as a hand chain hoist) commonly used in factories is also a pulley block. Pulley blocks are widely used in cranes, hoists, lifts and other machinery.
There are two types of pulleys: fixed pulleys and movable pulleys
(1) Fixed pulleys are essentially equal-arm levers, which are effortless and effortless, but can change the direction of the force.
Characteristics of the fixed pulley
It is not labor-saving to use the fixed pulley to pull the hook code.
The reading of the spring balance is the same with or without the fixed pulley. It can be seen that using a fixed pulley does not save effort but can change the direction of the force. In many cases, changing the direction of the force will bring convenience to the work.
The principle of the fixed pulley
The fixed pulley is essentially an equal-arm lever. The power L1 and resistance L2 arms are equal to the radius of the pulley. According to the lever balance condition, it can also be concluded that the fixed pulley is not labor-saving.
(2) The moving pulley is essentially a power arm acting as a resistance...gt;gt;
Question 4: What types of roller skating events are there? Types of Michael Midland Roller Skating Events
1. Freestyle SLALOM
It combines freestyle skating, traditional skating, and hip-hop movements to create a freestyle skating experience.
Stake, obstacle speed, stop, jump, block, wheel dance, etc. make in-line skating more fun.
2. Figure Skating Artistic Skating
Roller skating events similar to figure skating include four basic competition events: prescribed figures, free skating, pairs skating and dance.
3. Speed ??skating SPEED
It is a roller skating competition similar to speed skating. It is divided into field races, road races, marathons, etc.
4. Roller Hockey HOCKEY
It is a roller skating sport with fierce competition. Players wear double or single skates and hold sticks in their hands to compete. Each side of the game has 4 field players and a goalkeeper.
5. Extreme roller skating X-Game
It is one of the most exciting sports events and is extremely popular among teenagers. With equipment as the main activity background, such as U-channel.
Hope this helps you
Question 5: What are the formulas for pulleys? 30 points The fixed pulley can change the direction of the force, but it cannot save effort. The movable pulley can save half the force, but it cannot change the direction of the force.
Question 6: What are the wire rope pulley specifications? The wire rope direction change pulley is designed according to the diameter of the wire rope. Generally It is 40-60 times the diameter of the wire rope. If the diameter of the wire rope is 10 mm, the corresponding sheave diameter is 400-600 mm, which is for reference only.
Commonly used steel wire ropes include phosphate-coated steel wire ropes, galvanized steel wire ropes, stainless steel wire ropes or plastic-coated steel wire ropes. They are used in atmospheric environments. The manganese-based phosphate-coated steel wire ropes produced with patented technology have the longest service life and are heavy-duty. For corrosive environments, hot-dip galvanizing-phosphating double-coated steel wire ropes are preferred. The phosphating coating improves the wear resistance and corrosion resistance of the steel wire. The resistance to wear and corrosion is the reason for increasing the service life of the steel wire rope. Smooth steel wire ropes are being completely eliminated.
For phosphating coated steel wire ropes, manganese or zinc-manganese phosphating is preferred. Compared with the production process of smooth steel wire ropes, it only adds a wear-resistant phosphating treatment process before making the rope. The wear resistance of the steel wire is The strength and corrosion resistance are greatly improved, and the phosphated steel wire is directly twisted into a steel wire rope without cold drawing. Current fatigue test data shows that the fatigue life of phosphate-coated steel wire ropes is about three times that of smooth steel wire ropes with the same structure (under comparable conditions in the laboratory). It is not easy to wear and rust, which is the reason why the service life of steel wire ropes is greatly extended. It has far exceeded Imported wire rope. Manganese phosphate coating can solve the wear problem of steel wire ropes during use and improve corrosion resistance. For reference only
Question 7: How many types of roller skating are there? Currently, the popular types of roller skating in the world are as follows: Types:
Fitness, Aggressive, Hockey, Freeskate, Speed, Slalomn, Slide, Downhill, Jump, Step-in, Catching, Towed, Artistic, Basket, Dance, Off-road
1. Fitness.
Generally refers to street skating, which is the most popular form of recreational roller skating. Some aging urbanites abroad regard roller skating as a form of fitness, just like running, or as a means of transportation. So there are no technical requirements for it, as long as it can slide forward, stop, and turn. In addition, the difference between outdoor roller skating activities such as traveling from one city to another and speed skating is that the speed is intermediate, and the distance covered is generally less than 40KM.
2. Aggressive. Generally refers to extreme roller skating, which is a special form of roller skating. These include "STREET" (block) and "RAMP" (U-shaped pool), each using various techniques to interpret their own understanding of "limit".
3. Hockey. What we are talking about here is roller hockey. The main types of hockey are: Roller hockey, Inline hockey, Street hockey, and Ringettes. Each type of hockey has differences in details such as court, ball, club, and golf knife.
4. Freeskating. This is what everyone often calls FSK. Freeskating can be translated as "freestyle roller skating". It is a very new roller skating event. It has only been new in Europe for two or three years. Its main source of inspiration is the speed of Fitness and the skills of Aggressive, and combines downhill, speed skating, and acrobatic rollerskating. It is a brand new way of playing that reflects the development of modern roller skating. At present, it has become a symbol of urban roller skating spirit in Europe and the United States
5. Speed. Generally refers to speed skating, including track races, short track races, etc. The difference from other roller skating is mainly in its speed and professional configuration.
6. Slalom. This refers to flat flowers, which mainly include Freestyle Slalom and Speed ??Slalom. The currently popular flat roller skates mainly use single-row roller skates. In some European cities, double-row roller skates (quads) are also used to play flat roller skates. The wheels of these flat roller skates are generally relatively small. They are as soft as 78A and are very different from the double-brand roller skates we commonly use to practice figure skating on indoor wooden floors. The main reason is that one wheel is suitable for indoor use and the other is suitable for outdoor use.
7. Slide. This refers to braking technology, sometimes also called flat braking (Cess Slide). Its purpose is to stop the vehicle in a short time under different conditions. Personally, I think its content, style and difficulty level are quite different from Slalomn, so it is called a separate category. Among the more well-known technical actions are: power slide, parallel slide, magic, acid, etc.
8. Downhill. What this refers to is downhill. Judging from the name, we know that it should be a process of quickly sliding from a high mountain to the end of the mountain. Its risk factor and difficulty level are a challenge even for a relatively skilled speed skater. The speed of rushing down the mountain can often reach 70kph-80kph. For untrained skaters, it is relatively difficult. It's hard to handle such speed. As far as the equipment is concerned, speed equipment is generally used. In addition, helmets and a full set of protective gear are required during competition. In addition, according to the laws of some European countries, such as France, downhill riding on public roads is prohibited, mainly for safety reasons.
9. Jump.
This refers to jumping, which includes: Style Jump or Figure Jump, Acrobatic Jump or Pure Height, High Platform Jump...gt;gt;
Question 8 ：How many types of sliding door pulleys are there? There are two common pulleys on the market: ordinary pulleys and buffer pulleys. Wrigley wardrobes basically use buffer pulleys with resistance
They have low impact force, low noise and long service life when pushing and pulling.