A physics problem in the third year of junior high school

A is the analogy method, that is, the current is compared to the flow of water, so that the characteristics of the current can be vividly depicted;

b is to do experiments, or it can be said to express phenomena that cannot be directly or visibly observed in another way.

c is an equivalent substitution, because in that case the frictional force is equal to the tensile force when the two forces are balanced.

I don't know for sure, maybe it's because the use of smooth planes is in an "ideal state", which is equivalent to removing all other forces from the intervention study, and it is equivalent to shaping a model......

Anyway, I ruled out the ...... of ABC's choiceFor LZ reference only......

A uses an analogy. b is an experiment, and the phenomenon of the experiment can be observed intuitively, rather than abstractly. c is also an experiment, which can be done, so that the object is in a state of uniform linear motion, so as to find the sliding friction.

The smooth plane in d means that there is no friction, which is impossible in real life, so it is an abstract "model", such as Galileo's ideal experiment.

A smooth planar type is an ideal plane, which is characterized by the absence of resistance, which is also the main object of study, just as when we are studying an object that can ignore its volume, we can treat it as a particle. In physics, we must learn to grasp the main contradiction and ignore some secondary contradictions that affect human analysis, which is very important for building a model, and establishing a reasonable and correct model is a quick and correct shortcut to solve the problem.

a is because the current is directional.

b is the use of the conversion method to study that the object occurs because the object is vibrating.

c is balanced by two forces.

d is an ideal state to minimize friction, which is negligible and avoids affecting the experimental results.

So the closest should be d

At present, mechanics mainly relies on the "Newton's three laws", again based on the development of mechanics.

The basic condition of mechanics is the study of the changes of an object that is not subject to any external force when it is subjected to force. Therefore, it is often assumed that a "smooth" plane is not forced, because an object on a smooth plane is not subjected to force. But in fact, like light, smooth horizontal planes cannot be constructed, that is, they do not exist objectively.

It's just an abstract way of thinking when people are studying a problem. And because light does not exist objectively, but is an abstract straight line that is convenient for people to analyze, so the question is more closely related to the question is d.

If you still don't understand, just bring it up and I'll tell you about it.

Hehe, I feel that the physics champion in high school didn't return all the knowledge to my teacher.

In physics research, an abstract "model" is often used to vividly highlight the main features of things.

The landlord understands it"Abstraction"meaning.

It is a model that does not appear in real life, an ideal model that depends on imagination.

achievable.

b is also available. c is also available.

D will not be there in real life, because there is friction everywhere, it is impossible to find a smooth enough horizontal plane, so it is consistent with the topic. Pick D