How to calculate the friction of square timber pile
Publish: 2021-05-27 03:17:59
1. The formula of sliding friction f = UN
where n is the pressure, and N = mg
u is the sliding friction coefficient on the horizontal ground, which is related to the material.
friction
1, friction
(1) definition: when two objects in contact with each other are about to move or have moved relative to each other, they will proce a force on the contact surface to hinder the relative movement, This kind of force is called friction.
(2) the friction between objects must have the following three conditions:
first, the objects contact and squeeze each other
Second, the contact surface is not smooth
Third, there is a relative movement trend or relative movement between objects.
2 Sliding friction force
(1) definition: the friction force generated when an object slides on the surface of another object is called sliding friction force.
(2) the experiment to study the relationship between the size of sliding friction force and which factors: why do we use the spring scale to pull the wood block to do uniform linear motion in the experiment? This is because the spring scale measures the tensile force, not the friction force. When the wood block moves in a straight line at a uniform speed, the horizontal tensile force of the wood block and the friction force of the board against the wood block are a pair of balance forces. According to the condition of the balance of the two forces, the tensile force should be equal to the friction force. Therefore, measuring the tensile force is also measuring the friction force, The greater the pressure is, the greater the sliding friction is; The coarser the contact surface is, the greater the sliding friction is.
(3) the sliding friction is the force that hinders the relative motion of objects in contact with each other, not necessarily the force that hinders the motion of objects, It should be clear that the object in contact with each other is used as the reference to hinder the "relative motion". The "object motion" may use other objects as the reference. For example, in the experiment, when a weight is placed on the wood block and the spring scale is used to pull the wood block to move at a uniform speed in a straight line, The specific situation is: when the wood block is pulled forward from static, the weight will slide backward relative to the wood block, and the wood block will give the weight a friction force to prevent it from sliding backward. The direction of the friction force is forward. Therefore, the weight does not slide relative to the wood block, In this case, the friction is static friction.
(4) the sliding friction has nothing to do with the speed of the motion of the object, and has nothing to do with the size of the contact area between objects.
(5) in order to simplify the practical problems, we often use the "idealized" method, such as one object is placed on the smooth surface of another object, which means that if two objects move relative to each other, the "smooth" method is used, There is no friction between them.
3. Static friction is proced by the interaction of two mutually stationary objects. The direction of static friction can be the same as or opposite to the direction of force.
4, Due to the deformation of two objects in contact, the rolling friction is called rolling friction
where n is the pressure, and N = mg
u is the sliding friction coefficient on the horizontal ground, which is related to the material.
friction
1, friction
(1) definition: when two objects in contact with each other are about to move or have moved relative to each other, they will proce a force on the contact surface to hinder the relative movement, This kind of force is called friction.
(2) the friction between objects must have the following three conditions:
first, the objects contact and squeeze each other
Second, the contact surface is not smooth
Third, there is a relative movement trend or relative movement between objects.
2 Sliding friction force
(1) definition: the friction force generated when an object slides on the surface of another object is called sliding friction force.
(2) the experiment to study the relationship between the size of sliding friction force and which factors: why do we use the spring scale to pull the wood block to do uniform linear motion in the experiment? This is because the spring scale measures the tensile force, not the friction force. When the wood block moves in a straight line at a uniform speed, the horizontal tensile force of the wood block and the friction force of the board against the wood block are a pair of balance forces. According to the condition of the balance of the two forces, the tensile force should be equal to the friction force. Therefore, measuring the tensile force is also measuring the friction force, The greater the pressure is, the greater the sliding friction is; The coarser the contact surface is, the greater the sliding friction is.
(3) the sliding friction is the force that hinders the relative motion of objects in contact with each other, not necessarily the force that hinders the motion of objects, It should be clear that the object in contact with each other is used as the reference to hinder the "relative motion". The "object motion" may use other objects as the reference. For example, in the experiment, when a weight is placed on the wood block and the spring scale is used to pull the wood block to move at a uniform speed in a straight line, The specific situation is: when the wood block is pulled forward from static, the weight will slide backward relative to the wood block, and the wood block will give the weight a friction force to prevent it from sliding backward. The direction of the friction force is forward. Therefore, the weight does not slide relative to the wood block, In this case, the friction is static friction.
(4) the sliding friction has nothing to do with the speed of the motion of the object, and has nothing to do with the size of the contact area between objects.
(5) in order to simplify the practical problems, we often use the "idealized" method, such as one object is placed on the smooth surface of another object, which means that if two objects move relative to each other, the "smooth" method is used, There is no friction between them.
3. Static friction is proced by the interaction of two mutually stationary objects. The direction of static friction can be the same as or opposite to the direction of force.
4, Due to the deformation of two objects in contact, the rolling friction is called rolling friction
2. The calculation method of sliding friction is different from that of static friction. When solving the friction, we must distinguish static friction from sliding friction.
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
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
3. 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
4. Now mining is hot again. As a result, the price of graphics card increases, and that of second-hand ones also increases
if it's gtx10606g, the second-hand one is about 1700. If it's 3G, it's about 1300.
if it's gtx10606g, the second-hand one is about 1700. If it's 3G, it's about 1300.
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just like Taobao, you can edit your baby into online information and publish it overseas through the express platform. Similar to the domestic delivery process, the baby is transported to the buyer through international express delivery. In this way, it is easy to enter into transactions with buyers from more than 220 countries and regions and earn US dollars. However, in order to protect domestic e-commerce and restrict or prohibit cross-border online shopping, Russia and Argentina have implemented corresponding policies.
Global Express is Alibaba's online trading platform for the global market, which is known as the international version of "Taobao" by the majority of sellers
just like Taobao, you can edit your baby into online information and publish it overseas through the express platform. Similar to the domestic delivery process, the baby is transported to the buyer through international express delivery. In this way, it is easy to enter into transactions with buyers from more than 220 countries and regions and earn US dollars. However, in order to protect domestic e-commerce and restrict or prohibit cross-border online shopping, Russia and Argentina have implemented corresponding policies.
6. How to calculate the friction force
two force balance or pressure multiplied by sliding friction coefficient
the calculation formula of sliding friction force is f= μ N. In the formula 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.
two force balance or pressure multiplied by sliding friction coefficient
the calculation formula of sliding friction force is f= μ N. In the formula 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.
7.
bus line: fast 70, the whole journey is about 16.4km
1. Walk about 460m from Shaoxing north station to Shaoxing North Station
2. Take fast 70, after 6 stops, to the passenger transport center station
3. Walk about 1.2km to Donghu street
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