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Anonymous users2024-02-13Friction is only related to the amount of pressure and the roughness of the contact surface, when people are walking, friction is the driving force, so the bigger the faster, and you climb the pole is your body, and the relative rod has a downward trend, so the friction is up.
The center of gravity of an irregular object can be found using the hanging off method. Determine a point first, drop a heavy object, then the line must find another point through the center of gravity, repeat the above process. So two points come together at one point, and that point is the center of gravity of the plank!
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Anonymous users2024-02-12Friction is divided into two main categories: sliding friction and static friction!
To put it simply, sliding friction is the friction that occurs on the contact surface when there is relative sliding between objects. For example, if a car kills a car, it can drag a trail on the ground, which is the result of sliding friction! The same car starts killing at the same speed, and the less backward sliding friction it is subjected to, the farther it will slide!
Friction is sometimes used as a driving force, for example, without friction a person cannot walk. Friction is only related to the amount of pressure and the roughness of the contact surface. Measured by the heavy vertical method, any 2 corners of the irregular object are pulled, and after stationary, the intersection of the 2 pulled action lines is the center of gravity.
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Anonymous users2024-02-11Friction is divided into static friction and sliding friction, and walking is static friction. The sliding friction is related to the pressure and the roughness of the contact surface, that is, the dynamic friction factor (f friction n pressure dynamic friction factor), static friction and force. Since the climbing lever has the gravitational pull of the earth, the person has a downward tendency, so the friction force is upward.
The center of the irregular object is at the center of the geometry.
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Anonymous users2024-02-10Why don't you walk faster with less friction?
It's a matter of force and speed, for example, if there's a lot of friction, people won't necessarily be able to walk. There is no equivalence.
Is friction related to anything other than the pressure and roughness of the contact surface?
Friction is divided into static friction and sliding friction The pressure is related to the roughness of the contact surface (dynamic friction factor), and the direction of friction is opposite to the direction of relative motion of the object, so why is the friction force upward and the friction force is upward when climbing the lever?
Due to the gravitational pull of the earth, people have a relative downward tendency, so the friction is upward.
Please tell us more about friction.
By the way, where is the center of gravity of an irregular object?
The center of gravity of an irregular object can be found using the hanging off method. For example, if a wooden board is determined first, and a heavy object is dropped, the line must pass through the center of the circle. Find a little more and repeat the process above. So two points come together at one point, and that point is the center of gravity of the plank!
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Anonymous users2024-02-09The direction of friction is opposite to the direction in which the relative motion between objects occurs. Its size is related to the pressure and roughness between the contact surfaces, as well as the properties of the material between the contact surfaces, such as hardness.
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Anonymous users2024-02-08Irregularities can be found by cutting and repairing
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Anonymous users2024-02-071.Because b does a uniform linear motion in the horizontal direction.
So b is balanced by force in the horizontal direction.
Whereas, B has only the friction of A in the horizontal direction.
Therefore, the friction force is 0
2.To ab as a whole.
Let the ground friction factor be U, and the AB mass is m
The first time AB does a uniform linear motion.
Therefore, the friction of a is balanced with f1.
Therefore, F1 = U 2mg
The second time AB does a uniform linear motion.
Therefore, the friction against AB is balanced with F2.
Therefore f2=umg 2=f1=12 (Ox).
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Anonymous users2024-02-06A force f acts on a and there is no friction between ab, so the friction force on b is 0n;
B f=12n Reason: The frictional force of the ground facing the whole AB in Figure A is f=U(Ga+GB)=12N
The friction of the ground towards a at a constant velocity in B UGA + the friction force on b UGA = F2 = 12N
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Anonymous users2024-02-05The first void, because it is moving at a uniform velocity, the net force experienced is zero, so the frictional force is equal to the applied force is equal to 12N. In the second space, you use the formula of friction to find that when these two objects move together, the frictional force is the same, so the frictional force is still 12n, because the constant velocity, the net force is zero, so the reasoning f2 is equal to 12n.
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Anonymous users2024-02-041, 0n because ab together do uniform linear motion, according to Newton's laws. At this time, the external force of object B is zero, and looking at the diagram, there is only a pair of equilibrium forces acting on B, that is, the gravity force and the vertical upward support force of A to B, and there is no acceptance on the horizontal plane, so the friction force is zero.
The magnitude of the 2, 12n friction force is independent of the contact area.
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Anonymous users2024-02-03Friction divides friction and static friction.
Kinetic friction is further divided into sliding friction and rolling friction.
The sliding friction is determined by the kinetic friction factor and the positive pressure. Magnitude of force = coefficient of friction Positive pressure, rolling friction in the high range is rarely involved.
Static friction is determined by the force experienced by the object.
Objects are analyzed by force, but static friction is not only present in stationary objects, but also in moving bicycles, and the front wheels of a bicycle are also powered by static friction. The box moving on the belt is also subject to static friction.
Static friction can be abruptly changed to sliding friction.
Hope it works for you.
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Anonymous users2024-02-02Friction divides friction and static friction. The kinetic friction force is determined by the kinetic friction factor and the positive pressure. Static friction is determined by the force experienced by the object. Take something and practice it yourself!! Hehe.
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Anonymous users2024-02-01Landlord, you are wrong, it is impossible to pull an object at a uniform speed with a force of 6n for the first time, and the second time you pull an object with a force of 9n is not an object in uniform motion!
The frictional force required for all the forces required for uniform motion is 6N!
If you pull with a force of 9n for the second time, the friction force is still 6n!
Hope landlord!
The generation of rolling friction is caused by the deformation at the contact point between the object and the plane. The object is pressed into the bearing surface by gravity, and at the same time it is also deformed by compression, so when rolling forward, the bearing surface in front of it is uplifted, which makes the point of action of the elastic force n of the support facing the object move forward from the lowest point, so the elastic force n and gravity g are not in a straight line, but form a force couple moment that hinders rolling, which is rolling friction. The magnitude of rolling friction is measured by the coupling moment, and is proportional to the positive pressure, and the proportional coefficient is called the rolling friction coefficient δ, which is numerically equivalent to the elastic force to the force arm of the center of mass of the rolling object, so it has a dimension of length; It is related to the material, hardness and other factors of the rolling object and the bearing surface, and has nothing to do with the radius. >>>More
The first belongs to rolling friction, the essence of rolling friction is to produce a drag moment, that is, the support force of the ground is no longer directed to the axis of the wheel, but there is a forward offset in one direction, this offset produces a moment that hinders the rotation of the wheel, making the rotation slower, if the wheel and the horizontal plane are ideal rigid bodies, if they do not deform, they are not subject to rolling friction and move forever, even if the contact surface is rough. >>>More
This question should be considered in two processes:
1.Because when only F1 is added, the object moves in a uniform straight line to the east, so the sliding friction is 10N to the west, remove F1, and add F2 until the object velocity is 0, the object velocity direction remains unchanged, so the sliding friction of the object is still 10N to the west. >>>More
If the tension increases from zero, the friction force decreases to zero after applying the tension force and then gradually increases along the inclined downward direction, and if you want to have acceleration upward, the tension force and the friction force cannot be in the same direction.
It's because there is static friction when it's stationary and sliding when it's sliding, and the two frictions aren't the same, and the maximum static friction is the same as sliding friction (note that static friction is not a fixed straight, but sliding friction is straight.