There is a type of physics question, from the second year of junior high school to the third year of high school, all junior high school students who do not seriously summarize the method of solving the problem often make mistakes again and again, which becomes the weakness of some students! The abilities involved in this type of question are so important that they are related to the success or failure of the high school entrance examination and even the college entrance examination!
This type of question is an image information question!
由于新课程标准重视跨学科实践的学习，而图像信息题正是运用数学图像直观揭示物理规律的题型。 在初中主要包括“s-t、v-t、m-v、U-I、温度时间图像、F-t、P-t、W-t、F浮-h、F拉-h、P-R、P-U……”等！
To successfully resolve such issues, you need to do the following:
1. See the physical quantities represented by the ordinate and abscissa in the image! (Also pay attention to the unit)
2. Study the changes in the image and determine the relationship between the two physical quantities! (i.e., to see how the ordinate physical quantity changes as the abscissa physical quantity increases)
3. It can be solved quickly with the help of mathematical tools! For example, proportional functions, inverse proportional functions, similar triangles, quadratic functions, etc.
Let's take a look at the image information questions that will be encountered in the final exam of the second year of junior high school, although it seems simple, but the error rate is not low!
The first and second year physical image information questions:
This question examines an image of the power of work done by gravity over time.
Let's start with the formula: P=GV.
First, find out the invariant - the gravity G of the paper cone does not change during the falling process;
Then find out the amount of change - it can be concluded that the paper cone first accelerates and then moves at a uniform speed, that is, V increases first and then does not change! From the mathematical relationship, it can be seen that P is proportional to V, (GV increases first and then does not change!) That is to say, P increases first and then does not change) so we can find an image that fits this trend and choose C.
The second question of physical image information in the second year of junior high school:
Using the same method as described above, let's start by writing the formula: P=FS=FVt.
Let's find out the invariants first - the tensile force F does not change, the speed V does not change!
Then find out the amount of change - time t change.
From the mathematical relationship, it can be seen that P is proportional to t, (with the uniform increase of t, W increases uniformly)! Therefore, choose B.
The third question of physical image information in the second year of junior high school:
Using the same method as described above, let's start by writing the formula: W=Gh.
Let's find out the invariant first - gravity G is constant!
Then find out the amount of change - the change in time t leads to the change in h, and the change trend of the two is shown in the figure.
From the mathematical relationship, it can be seen that W is proportional to h, (with the increase of time t, h becomes larger as shown in the figure, and W also tends to increase)! Therefore, choose B.
The fourth question of physical image information in the second year of junior high school:
There are four kinds of images in this question, so you need to decide whether to list or not according to the specific situation.
Let's start by identifying the invariants and the amount of change:
Let's find out the invariant first - the human gravity G and velocity V are constant!
Then find out the amount of change - time t change.
The image of option A represents the object doing accelerated motion, which does not meet the topic, and A is wrong.
Option B image represents the object at rest, which does not fit the topic, and B is wrong.
The CD option can list the mathematical relations as shown in the figure, and the C option can be seen from the mathematical relationship that W is proportional to t, (as time t increases uniformly, W increases uniformly)! The image doesn't match, C is wrong. The D option shows that P is a constant quantity, so D is correct.
From the above summary, it can be seen that in order to solve this kind of problem, we must grasp two points: reading the graph, columnarism, finding quantitatives and variables, and finding the image according to the mathematical relationship! In this way, such questions are not difficult problems. All junior high school students who do wrong must firmly grasp this method that must be commonly used now and in the future, come on!