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Anonymous users2024-02-071.If there is no extrusion between objects, there is no friction, that is, a stationary wooden block on a horizontal table is not affected by friction;
No, friction is equal to the coefficient of friction multiplied by pressure, and there is no friction without pressure; The static friction of a block on a stationary re-horizontal table is equal to the horizontal thrust, and there is no friction in the absence of thrust.
2.Suppose there is a wooden block on the horizontal tabletop, and the force of 5n is used to push it, the wooden block remains stationary, but the wooden block is still affected by the frictional force, which belongs to the two-force balance, and the friction force is 5n
Pair 3If there is no friction, people can't walk, right? But can it be pulled by traction?
Yes, walking is done by the friction of the soles of the feet. If there is no friction, the force of traction can come from the inertia of a moving object, and a person can be pulled.
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Anonymous users2024-02-061.There must be no friction if there is no extrusion between objects, but there is extrusion without relative motion or relative motion tendency without friction, so the stationary wooden block on the horizontal table is not necessarily subject to friction.
2.If the force of this 5n is horizontal, then it is correct. If it is not horizontal, it is the horizontal component of these 5n.
3.It can only be said that it is not good to rely on the friction of the soles of the feet to move, but it can be recoiled, purely rolling, taking an airplane, etc.
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Anonymous users2024-02-05If there is extrusion, there is touching force;
1) If there is no squeezing between objects, there is no friction, which is incorrect;
2) This is the static touch force, when the wooden block is just moving, this is its maximum static touch force.
3) If there is no friction, people can't walk right.
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Anonymous users2024-02-041 pair. 2 pairs.
3 Pairs The tow also has to be moved forward by friction, unless it is off the ground.
Physics is an interesting course, study hard, and strive to be admitted to the Department of Physics of China Normal University as my junior, hehe.
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Anonymous users2024-02-03Friction is related to the magnitude of the pressure and the roughness of the pressure surface.
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Anonymous users2024-02-02According to the proposal, because the whole process is not moving, the force A is subjected to the friction of B to the left, 8n
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Anonymous users2024-02-018nSince both objects are at rest, the resultant external force is zero by using Newton's second law for a, so the frictional force is 8n
In the same way, the friction between b and the ground is 3n
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Anonymous users2024-01-318n look at a, don't look at b, the force of a is very clear, the horizontal direction is only f=8n and friction, since it remains stationary, the friction must be equal to f, that is, 8n
B, the force is more complicated, there is a friction force on it, and there is also the friction of the ground, and the friction of the ground should be 5N, to the left.
It's not hard to figure this out.
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