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Four conditions for friction Is it 1. Objects contact and squeeze each other 2. The contact surface is not smooth 3. Relative motion or relative motion trend between objects 4. There is elasticity between objects
To generate friction between objects, the following four conditions must be met:
First: two objects are in contact with each other
Second: two objects squeeze each other, deform and have elasticity
Third: two objects have relative motion or relative motion trend
Fourth: the indirect contact surface of two objects is rough
What conditions are required for the generation of friction
To generate friction between objects, the following three conditions must be met:
First, objects contact and squeeze each other
Second, the contact surface is not smooth
Third, there is a trend of relative motion or relative motion between objects
To judge the direction of friction, why should we look at acceleration? For example, if an object is placed on the conveyor belt and the object is stationary relative to the conveyor belt, the direction of friction force on the object will change
There are three cases: first, the conveyor belt has a uniform speed. This is the trend that the acceleration of the object is 0 and there is no relative motion and relative motion with the conveyor belt, that is, the force is balanced in the direction perpendicular to the conveyor belt and there is no friction in the direction of the conveyor belt. Second, acceleration. At this time, the acceleration of the object is caused by the friction brought by the conveyor, At this time, the friction force on the object is consistent with the moving direction of the conveyor belt. Third, deceleration is actually equivalent to accelerating in the opposite direction of the moving direction of the conveyor belt. The object tends to slide in the moving direction of the conveyor belt. It is precisely because of the backward friction force brought by the conveyor that it is stationary relative to the conveyor belt rather than sliding in the moving direction of the conveyor belt. In conclusion, look at the direction of friction force, In fact, it is necessary to judge which direction the acceleration of an object is in, and the acceleration is generated because of the external force it receives: friction. I'm glad to answer for you. Please find a teacher
How to determine the direction of friction on the conveyor belt? 1. When an object is stationary on the conveyor belt, what is the direction of friction? 2. When an object accelerates on the conveyor belt, what is the direction of friction? Please explain why 3. When accelerating, the friction direction is consistent with the direction of the conveyor belt, However, the object does not move forward relative to the conveyor belt, so the friction Should it be backward? What's wrong with my analysis?
1. There are three situations when the conveyor belt is stationary ① the conveyor belt is stationary without friction! ② The conveyor belt moves at a constant speed without friction! ③ The conveyor belt moves in an accelerated straight line, and the friction force is the same as the acceleration direction! 2. When accelerating on the conveyor belt, the object is stationary relative to the conveyor belt, the acceleration of the two is the same, and the object is only subject to friction in the horizontal direction
Several cases of friction direction of objects on conveyor belt
Three cases (taking the ground as the reference system):
1. The speed of the object is less than the speed of the conveyor belt, the direction of the object subject to friction is consistent with the direction of motion, and the object accelerates;
2. The speed of the object is equal to the speed of the conveyor belt, and the object is not subject to friction;
3. The speed of the object is greater than the speed of the conveyor belt. The direction of the object subjected to friction is opposite to the direction of motion, and the object decelerates
The above is for the horizontal conveyor belt
The object on the conveyor belt determines the direction of friction The conveyor belt forms an angle of 30 ° with the ground, and the moving direction of the conveyor belt is the same as that of the object. When the object is put on, the initial speed is 0, and then it accelerates to the same speed as the conveyor belt. The original friction direction is the same as the moving direction. How to judge the friction direction next? What if the sliding friction is less than or greater than the component of gravity?
The resultant force of friction and supporting force counteracts gravity, so the direction of friction is still along the conveyor belt. If the conveyor belt is transported upward along 30 degrees and the sliding friction is less than the gravity component, the object will always slide at the bottom of the conveyor belt and cannot go up. If it is greater than the component, the last problem will occur. If it is transported downward, it will be in the gravity component
RELATED INFORMATIONS
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