What is friction and how to calculate it
Publish: 2021-04-29 02:46:03
1. Usdt is different from other currencies. It is not only issued based on one blockchain network. There are corresponding usdt tokens issued on BTC, ETH, TRC and other networks. At present, usdt issued on BTC and eth networks is the most commonly used one. Usdt in different networks are not interconnected. That is, if you use BTC_ Usdt transfer to eth_ Usdt is certainly not successful
there will be bitcoin chain and Ethereum chain when choosing the recharge address of the exchange. If you have a good choice, you can contact bitcom online customer service
there will be bitcoin chain and Ethereum chain when choosing the recharge address of the exchange. If you have a good choice, you can contact bitcom online customer service
2. You can't withdraw money, can you? help
3. Friction refers to the force that hinders the relative motion (or relative motion trend) of an object. Its direction is opposite to the relative motion (or relative motion trend) of the object. Friction is divided into static friction, rolling friction and sliding friction. The sliding friction is related to the roughness of the contact surface and the pressure. The larger the pressure is, the rougher the contact surface is, and the greater the sliding friction is
friction is related to objects that rub against each other, so the description of friction in physics is not general, nor is it as accurate as other forces. Without friction, shoelaces can't be fastened, and screws and nails can't hold objects
the biggest difference in friction is between static friction and other friction. Some people think that static friction should not actually be counted as friction. Other frictional forces are related to dissipation: it reces the relative velocity of objects that rub against each other and converts mechanical energy into heat energy< The friction between solid surfaces can be divided into sliding friction, rolling friction, static friction, rolling friction and rotational friction. In engineering technology, people use lubricating oil to rece friction. If two surfaces are separated by a layer of liquid, liquid friction can occur between them. If the separation of liquid is not complete, mixed friction may also occur. Air track works by air friction. The working principle of lubricating oil and air track is to use "liquid or gas (i.e. fluid) friction to replace solid friction" to work
If lubricating oil, liquid or gas flows along a solid surface, its velocity will be reced e to the influence of friction. The structure of the solid surface has little effect on the friction, and the most important one is the cross-sectional area of the fluid. The reason is that there is friction not only at the interface between the fluid and the solid, but also between different layers in the fluid, and the velocity of the fluid varies with the distance from the solid surface
an object moving relative to a fluid is resisted. This resistance is in the opposite direction of its motion. In the case of laminar flow, the resistance is proportional to its velocity. In turbulence, the resistance is proportional to the square of its velocity. Sometimes an object is subject to resistance and friction at the same time. For example, when a car is moving, it is subject to the resistance of air and the rolling friction of its tires Friction sometimes makes objects move, unlike resistance.)
friction is related to objects that rub against each other, so the description of friction in physics is not general, nor is it as accurate as other forces. Without friction, shoelaces can't be fastened, and screws and nails can't hold objects
the biggest difference in friction is between static friction and other friction. Some people think that static friction should not actually be counted as friction. Other frictional forces are related to dissipation: it reces the relative velocity of objects that rub against each other and converts mechanical energy into heat energy< The friction between solid surfaces can be divided into sliding friction, rolling friction, static friction, rolling friction and rotational friction. In engineering technology, people use lubricating oil to rece friction. If two surfaces are separated by a layer of liquid, liquid friction can occur between them. If the separation of liquid is not complete, mixed friction may also occur. Air track works by air friction. The working principle of lubricating oil and air track is to use "liquid or gas (i.e. fluid) friction to replace solid friction" to work
If lubricating oil, liquid or gas flows along a solid surface, its velocity will be reced e to the influence of friction. The structure of the solid surface has little effect on the friction, and the most important one is the cross-sectional area of the fluid. The reason is that there is friction not only at the interface between the fluid and the solid, but also between different layers in the fluid, and the velocity of the fluid varies with the distance from the solid surface
an object moving relative to a fluid is resisted. This resistance is in the opposite direction of its motion. In the case of laminar flow, the resistance is proportional to its velocity. In turbulence, the resistance is proportional to the square of its velocity. Sometimes an object is subject to resistance and friction at the same time. For example, when a car is moving, it is subject to the resistance of air and the rolling friction of its tires Friction sometimes makes objects move, unlike resistance.)
4. Before calculating the friction force, we must first analyze the motion of the object to determine whether it is static friction or sliding friction. If it is sliding friction, the formula
F
can be used= μ N
calculation, where μ
is the friction coefficient; If it is static friction, it is usually solved according to the motion of the object (static, uniform motion, or variable speed motion) by using the equilibrium condition or the law of motion
to determine the direction of sliding friction, we must grasp the judgment basis of "the direction of sliding friction is opposite to the relative movement direction of the object". The specific method is: first select the object subject to friction as the research object, and then take the object in direct contact with the research object as the reference object, find out the speed direction of the research object relative to the reference object, then the direction of sliding friction is opposite to the direction of the relative speed
the basis for judging the direction of static friction is: "the direction of static friction is always tangent to the contact surface and opposite to the direction of relative motion trend of the object". The specific method is: firstly, select the object subject to static friction as the research object, and then select the object in contact with the research object as the reference object, and then assume that the contact surface is smooth to judge the velocity direction of the research object relative to the reference object, that is, the relative motion trend direction. Then, the direction of static friction is opposite to the direction of relative motion trend.
F
can be used= μ N
calculation, where μ
is the friction coefficient; If it is static friction, it is usually solved according to the motion of the object (static, uniform motion, or variable speed motion) by using the equilibrium condition or the law of motion
to determine the direction of sliding friction, we must grasp the judgment basis of "the direction of sliding friction is opposite to the relative movement direction of the object". The specific method is: first select the object subject to friction as the research object, and then take the object in direct contact with the research object as the reference object, find out the speed direction of the research object relative to the reference object, then the direction of sliding friction is opposite to the direction of the relative speed
the basis for judging the direction of static friction is: "the direction of static friction is always tangent to the contact surface and opposite to the direction of relative motion trend of the object". The specific method is: firstly, select the object subject to static friction as the research object, and then select the object in contact with the research object as the reference object, and then assume that the contact surface is smooth to judge the velocity direction of the research object relative to the reference object, that is, the relative motion trend direction. Then, the direction of static friction is opposite to the direction of relative motion trend.
5. 1.
f = μ N
2.
μ Is the friction factor
n is the pressure of an object on another object
If an object is on the ground, its pressure on the ground is n = mg
3.
If a body is subjected to a force without relative motion, then the friction force is equal to the force on the body.
f = μ N
2.
μ Is the friction factor
n is the pressure of an object on another object
If an object is on the ground, its pressure on the ground is n = mg
3.
If a body is subjected to a force without relative motion, then the friction force is equal to the force on the body.
6. First of all, judge whether it is static friction or sliding friction. Static friction should be formulated according to Newton's second law. If it is in an equilibrium state, it can also be formulated as an equilibrium equation. If it is sliding friction, use f = UN, and remember that it is multiplied by elastic force, which is not necessarily equal to gravity
7. When calculating the size of friction, we should first judge whether the friction is sliding friction or static friction, and then use the corresponding method to find out.
the formula for calculating the size of sliding friction is f= μ N, where μ Dynamic friction coefficient, also called sliding friction coefficient, is only related to material and roughness of contact surface, but has nothing to do with contact area; N is the positive pressure.
sliding friction: the force that occurs between two objects that contact each other and slide relative to each other, and prevents them from sliding relative to each other.
the direction of friction is opposite to the direction of relative motion or the direction of relative motion trend of the object, but not opposite to the direction of motion of the object. Friction can be used as power or resistance
the formula for calculating the size of sliding friction is f= μ N, where μ Dynamic friction coefficient, also called sliding friction coefficient, is only related to material and roughness of contact surface, but has nothing to do with contact area; N is the positive pressure.
sliding friction: the force that occurs between two objects that contact each other and slide relative to each other, and prevents them from sliding relative to each other.
the direction of friction is opposite to the direction of relative motion or the direction of relative motion trend of the object, but not opposite to the direction of motion of the object. Friction can be used as power or resistance
Hot content