In the eighth grade, there is one set of physics (People's Education Edition) and one set of mathematics (Beijing Normal University Edition). . . This is a bit difficult.

Note: The value of G used in this volume is 10N/kg.

First, multiple-choice questions 1. The rainbow after the rain is beautiful. According to your physical knowledge and your usual observation, the correct information you can get from it is

A. the rainbow itself is a color light source B. the rainbow is formed by the dispersion phenomenon of light.

C. rainbows can only appear after rain in summer. When there is no sunshine, the rainbow is clearer

2. When taking a group photo, when the photographer auditioned, he found that the students on both sides did not take pictures. The photographer should

A. Move the camera forward and the lens will shrink inward. C. Move the camera forward and the lens will extend outward.

B. Move the camera backward, and the lens will shrink inward. D. Move the camera backward, and the lens will extend outward.

A drop of water fell on the textbook, and Wang Hai observed that the words on the textbook became bigger. The reason for this phenomenon is that

A. specular reflection of light B. linear propagation of light C. diffuse reflection of light D. refraction of light

4. How did Newton's first law of motion come about in physics?

A. simple experimental method B. simple speculative method C. mathematical deduction method D. experiment plus speculative method

When Xiao Ming was doing the experiment, he found that the data he measured was different from that measured by the teacher. What do you think is his mistake?

A. question the teacher's data B. modify your own data to make it consistent with the teacher's data.

C. Check whether your experimental scheme is reasonable. D. Check whether there are any mistakes in your experimental process.

6. When someone paddles in the lake, what makes the boat and people move forward as a whole?

A. the thrust of water to pulp, the thrust of man to ship

7. When we hang the wall chart, we can draw a thick vertical line to check whether the picture is upright. This is done by using

A. gravity is proportional to mass. B. the direction of gravity is perpendicular to the supporting surface.

C. the center of gravity is at the center of gravity of object d, and the direction of gravity is always vertical downward.

8. In the following instruments, the principle of communication equipment is not applicable.

A. Sprinkler B. Ship lock C. Boiler water level gauge D. Mercury barometer

9. Put the chalk box on the horizontal table. In the following description of the stress on the chalk box, the statement is correct.

A it is supported by gravity, friction, pressure and the platform. B.it is supported by gravity, pressure and the platform.

C it is supported by gravity, friction and platform. D. it is supported by gravity and platform.

10. As shown in Figure 1, the volume of the bubbles spit out from the fish mouth will gradually increase when they rise to the water surface, so the changes of buoyancy and gas pressure in the bubbles are as follows.

A. the buoyancy is constant and the pressure is constant. B. the buoyancy becomes smaller and the pressure becomes smaller.

C. buoyancy increases and pressure increases. D. buoyancy increases and pressure decreases.

1 1. The TV set placed on the horizontal desktop is subjected to mutually balanced forces.

A. the gravity of the TV and the support of the desktop to the TV

B. the gravity of TV and the pressure of TV on the desktop

C. The pressure of the TV set on the desktop and the support of the desktop on the TV set

D. The pressure of TV on the desktop and the gravity of the desk

12. A farmer poured mung beans into a container full of water when he was giving birth to mung beans, and found that the mature and full mung beans sank to the bottom of the water, and the withered and moth-eaten mung beans floated on the water. The reason for this phenomenon is that

A. Submerged mung beans have small buoyancy specific gravity, while floating mung beans have large buoyancy specific gravity.

B. The buoyancy of submerged mung beans is less than gravity, and the buoyancy of mung beans floating on the liquid surface is equal to gravity.

C. The buoyancy of submerged mung beans is greater than gravity, and the buoyancy of mung beans floating on the liquid surface is equal to gravity.

D, the buoyancy of submerged mung beans is equal to gravity, and the buoyancy of mung beans floating on the liquid surface is less than gravity.

Second, fill in the blanks (65438+ 0 points for each blank, ***20 points)

13. Which parts of the bicycle you are using make use of beneficial friction? Please give two examples and fill in the following lines: (1) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; (2)____________________ 。 In order to reduce harmful friction, what measures have you taken to use bicycles? A: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ refers to

14. As shown in Figure 2 (a) and (b), (a) shows that force can change an object; (b) Description: Force can change objects.

15. As shown in Figure 3(a), put the inflated balloon on the table and press it with the palm of your hand. You can see that the balloon is crushed, and the greater the force, the balloon will expand. Then hold the balloon with both hands, with one hand flat on the balloon and the other hand holding the balloon, as shown in Figure 3(b). It can be seen that the part where the balloon contacts the palm is deformed (fill in "obvious" and "inconspicuous"), while the part where the balloon contacts the finger is deformed. The physical truth revealed by the experiment made by Dahan Network Dahan Edition Publishing System is that.

16. The tension brought by modern life can be relieved by floating therapy. There is a certain depth of water in the floating pool, and there is a lot of _ _ _ _ _ _ _ _ _ water.

17. For safety, cars nowadays are generally equipped with seat belts and airbags. The width of the seat belt is relatively large for pressure; When a car has a serious collision, the airbag will automatically inflate and pop up, so that people in the car will not hit the body because of it.

18. As shown in Figure 4, the human eyeball is like a camera, and the interaction between the lens and the cornea is equivalent to a _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

19. Physics is everywhere in life: (1) People living in the western plateau often cook food by frying and baking, which is due to the high atmospheric pressure and boiling point of water in the plateau; (2) As shown in Figure 5, two plastic pipes B and C are often inserted into the bottle mouth A of the liquid medicine, in which the purpose of inserting the pipe C is to carry out the infusion smoothly. When inserting the needle, the nurse should check whether there is "blood return" (that is, blood flows from the needle into the infusion tube) to judge whether the needle is correctly inserted into the blood vessel. If there is "blood return", it means that the needle is inserted correctly, otherwise it will be stabbed again. The reason for "blood transfusion" is that the pressure of blood at the needle (fill in "greater than", "equal to" or "less than") is the pressure of the liquid medicine. This is necessary to prevent blood from flowing back.

Three, drawing questions (2 points per figure, ***6 points)

20. According to the incident light or refracted light in the two pictures in Figure 6, do the corresponding refracted light or incident light respectively.

2 1. As shown in Figure 7, the fish in the water spit out a string of bubbles, and the speed of the bubbles is getting faster and faster. The gravity of the larger bubble has been drawn. Please draw the buoyancy of the bubble again.

Four, experimental inquiry questions (***29 points) 22. (3 points) In the experiment of studying the imaging law of convex lens with optical bench:

(1) Measure the focal length of the convex lens as shown in Figure 8, from which we can know the focal length of the convex lens.

(2) Place the candle, convex lens and light screen on the optical bench in turn. After lighting the candle, roughly adjust the center of the candle flame, convex lens and light screen.

On the internet.

(3) When the distance between the candle flame and the convex lens is 15cm, the moving light screen can get a clear inverted image on the light screen, which works by using this imaging law (filling optical instruments).

23.(8 points) As shown in Figure 9, it is an experimental device to study the factors related to the magnitude of sliding friction, which reflects the process of small wooden blocks sliding along the horizontal plane under different conditions by spring dynamometer.

(1) From the purpose of the experiment, the primary problem to be solved in this experiment is: how to measure the force, please briefly explain the method and basis for solving this problem.

The practice is:

Based on:

(2) By observing the scenes in Figure A and Figure B, we can know that this is to study the relationship between sliding friction and friction under the same conditions.

24.(5 points) Through learning, students know the characteristics of liquid pressure. On this basis, the teacher asked a question: there are two cups filled with water and salt water respectively, but there is no label. Can you tell them apart with a pressure gauge?

(1) When the metal box of the pressure gauge is in the air, the liquid level on both sides of the U-shaped tube should be uniform, but the scene observed by Xiao Ming is shown in figure 10(a). The reason for this situation is that the air pressure above the liquid level of the left branch pipe of the U-shaped pipe is _ _ _ _ atmospheric pressure (fill in "greater than", "less than" or "), and the adjustment method is: ().

A. At this time, pour out the higher liquid in the right branch pipe. B. remove the hose and reinstall it.

(2) Xiao Ming draws the check shown in (b) again. When he pressed the rubber membrane with his fingers (whether it was light pressure or heavy pressure), he found that the height of the liquid column on both sides of the U-shaped tube was almost unchanged. The reasons for this situation are: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(3) After the pressure gauge is adjusted normally, Xiao Ming immerses the metal box into two cups of liquid successively, as shown in Figures (c) and (d). He found that there was a big difference in the height of the liquid column on both sides of the U-shaped tube in Figure (D), so he thought that the glass in Figure (D) was filled with salt water. Do you think Xiaoming's conclusion is (fill in "reliable" or "unreliable"); ② Briefly explain the reasons:

25.(7 points) According to Archimedes principle (F float =G drain) and related knowledge, it can be concluded that F float = ρ liquid V drain G, thus it can be seen that the buoyancy of an object is related to the object and the liquid.

Careful students further suggested that in addition to the above two factors, is buoyancy related to other factors? Among them, a more specific question is: Is the buoyancy of an object related to its shape? To solve this problem, if you were given the following equipment to choose from, which equipment would you choose and how to explore it?

Optional equipment includes: spring dynamometer, three small stones with different shapes, plasticine, beaker, string and water.

(1) The equipment you selected is:

(2) Your inquiry scheme (i.e. experimental steps) is:

(3) How do you draw a conclusion based on the observed phenomenon or the data obtained in the inquiry?

26.(6 points) Physical knowledge comes from life. To learn physics is to learn to observe life and to use electrical appliances in life to do experiments. Try to choose one or two given instruments, complete the experiment as required, and fill in the form according to the examples.

Appliances: glass (cylindrical flat bottom), cardboard, inflatable toy balloons (multiple), sponge, water (several).

Observation phenomenon of experimental content and operation method of instrument

Example: The force between two balloon objects is that two balloons are pressed together by both hands and deformed at the same time.

Relationship between pressure and pressure

The existence of atmospheric pressure

V. Comprehensive application questions (***2 1 minute)

27.(4 points) From 00: 00 on April 18, 2007, the sixth large-scale speed increase of China Railway was fully started. Railway experts say that when a train with a speed of 200 kilometers per hour passes by, the wind on one side of the railway is equivalent to a strong wind of magnitude 7, which exceeds the wind that people can bear. In other words, pedestrians along the railway may be sucked in if they are not careful. The railway department reminds the public that jaywalking will not only bring personal danger to the passer-by, but also bring great security risks to the train operation.

(1) An important physical law hidden in the above security problems is:

(2) According to the above law, when the train passes at high speed, the direction of strong wind rising by the roadside is ()

A. point to the train. Stay away from the train. C. the same direction as the garage. D. opposite the garage.

28.(3 points) In order to prevent forest fires, transparent liquid beverage bottles are not allowed to be discarded anywhere in the forest. Why?

29.(6 points) Due to the need of decoration, the floor of the lobby of a shopping mall is prepared to be paved with marble or other materials with high compressive capacity. In order to be beautiful and practical, Xiao Wang took the weights of two men and two women, recorded the area of single shoes in table 1, and investigated the pressure resistance of different materials, as shown in table 2. It is estimated that the hall can accommodate up to 200 customers. Please help Xiao Wang to choose suitable materials through calculation and comparison.

Table 1 Table 2

Gender Weight (Cattle) Plantar Area (cm2)

Male 600 200

Male 700 200

Female 500 150

Female 600 150

Maximum bearing pressure of material (Pa)

Wood floor 3.2× 104

Composite floor 3.8× 104

Vitreous fossils 8× 104

30.(8 points) People often use "the tip of the iceberg" to describe that only a small part of things are exposed and more are hidden under superficial phenomena. In fact, the iceberg really only shows a "tip" floating in the sea (as shown in figure 1 1), so how much does this exposed "tip" account for the size of the iceberg? Please use your knowledge of physics to explain in detail through calculation and short words.

Beijing normal university printing plate eighth grade mathematics volume two final examination questions

Multiple choice questions (3 points for each small question, 30 points for * * *)

If x>y, the error in the following formula is ()

a . x-3 & gt； y-3b . 3-x & gt； 3-y c . x+3 & gt； y+2 D。

On the number axis, the solution set of the inequality group indicates that the correct one is ().

A.B. C. D。

Given that the area of a square is (16+8x+x2)2, the perimeter of the square is ().

A.(4+x)b .(x+2)c .( 16+4x)d .(4x+8)

As shown in the figure, the following reasoning is given: ① Because ∠ 1=∠2, AD∨BC. ② Because AB∨DC, ∠3=∠4. ③ Because ∠ ABC+∠ C = 65436.

A.①②③ B.①②④ C.①③④ D.②③④

The following survey methods are applicable to ()

In order to know the service life of a batch of energy-saving lamps, a general survey was adopted.

Investigate the height of students in your class and take a sample survey.

The environmental protection department investigated the water quality of a section of Hanjiang River through sampling survey.

To investigate the bedtime of urban middle school students every day, and adopt the general survey method.

Solving the fractional equation shows that the solution of the equation is ()

A.x = 2 b.x = 4 c.x = 3 d. No solution.

As shown in the figure, the sides of small squares are all 1, so the triangle (shaded part) in the figure below is similar to △ABC ().

A. B.C. D

If ()

A.B. C. D。

If two sides of a right triangle are 6 and 8 respectively, and another right triangle similar to it is 3 and 4 and X respectively, then the value of X ().

There is only one A.B., there can be two C's, there are more than two C's, but there are countless D's.

As shown in the figure, in Rt△ABC, ∠ ACB = 90, BC = 3°, AC = 4°, and the extension line of the perpendicular line DE intersecting AB and BC is at point E, then the length of CE is ().

A. The second century BC

Fill in the blanks (this big question is ***8 small questions, each with 3 points and * * * 24 points).

Decomposition coefficient: 2m2-8m+8 = _ _ _ _ _ _

If _ _ _ _ _ _ _ _

The image with linear function y=kx+2 passes (-1, -2). Then when x _ _ _ _ _,

The function value is not less than 6.

As shown in the figure, if the straight lines m∨n, ∠ 1 = 55, ∠ 2 = 45, then the number of times of ∠3.

For _ _ _ _ _ _ _ _

As shown in the figure, CD is the bisector of the angle of △ACB. If you pass point B, you will BE⊥CD and your feet will droop.

For E, if we cross point E, let EF∨AB cross CB at point F, and it is known that ∠ A = 43 ∠ ACB = 58.

Then the degree of ∠FEB is _ _ _ _ _.

It is known that the inequality group about X has only four integer solutions, so the value range of real number A is _ _ _ _ _ _.

The variance of output per unit area (kg/mu) of two cotton farmers for five consecutive years is as follows:

Output of c

Time (year) First year, second year, third year, fourth year and fifth year.

Yield (kg/mu) 68 70 72 69 765 438+0

Then the variance of cotton farmers' unit output in C for five consecutive years is _ _ _ _ _ _, and the most stable unit output among the three cotton farmers is _ _ _ _ _

As shown in the figure, △ABC and △ a' b' c' are similar graphs, and the vertices are all on the grid, so the coordinates of the similar centers are _ _ _ _ _ _ _ _.

Answer (***7 small questions, out of 66 points)

(The full mark of this question is 8) Simplify first, and then evaluate:

Give three polynomials:. Please choose your favorite two polynomials to add and factorize the results.

(The full mark of this question is 10) Xiaoming wants to measure the height of a building with sunlight. He came downstairs to a building with a tape measure and found the shadow of the building on the opposite wall. In view of this situation, he designed a measurement scheme, and the specific measurement situation is as follows: For example, Xiao Ming observed while moving, and found that when he stood at point E, his shadow on the wall could overlap with the shadow of the building on the wall, and the height was exactly the same. The shadow height CD= 1.2m, CE=0.8m, Ca = 30m (points A, E and C are on the same straight line) when Xiao Ming falls on the wall. It is known that Xiao Ming's height EF is1.7m. Please help Xiao Ming find out the building height AB (the result is accurate to 0. 1m).

(Full score of this question 10) As shown in the figure, AB∑CD, AB=2CD, E and F are the midpoint of AB and BC respectively, and EF and BD intersect at point M. 。

(1) Try to explain △ EDM ∽△ FBM;

⑵ If DB=9, find BM.

(The full mark of this question is 10) Mingrun Supermarket bought a batch of new varieties of apples for trial sale with 5000 yuan. Due to the good sales situation, the supermarket allocated 1 1000 yuan to buy this variety of apples, but this time the purchase price was more than the 0.5 yuan per kilogram during the trial sale, and the number of apples purchased was twice as much as that during the trial sale. (1) What is the purchase price per kilogram of this variety of apples at the trial sale? (2) If the supermarket sells this variety of apples at the price of 7 yuan per kilogram, after most of the apples are sold, the remaining 400 kilograms are sold at a 30% discount ("30% discount" means 70% discount on the price), then how much profit does the supermarket make from these two apple sales?

(Full mark of this question 10) Students from Class 8 (3) participated in the "Green Olympics" knowledge contest organized by the school. The teacher divides the students' grades into segments with a group distance of 10, counts the frequency of each segment, fills in the frequency distribution table and draws the frequency distribution histogram. The frequency distribution table of class 8 (3) knowledge contest results.

Fraction segment (fraction) 49.5 ∽ 59.5 59.5 ∽ 69.5 69.5 ∽ 79.5 79.5 ∽ 89.5 ∽ 99.5

Group median (score) 54.5 64.5 74.5 84.5 94.5

Frequency A 9 10 14 5

Frequency 0.050 0.225 0.250 0.350b

Frequency Histogram of Class 8 (3) of "Green Olympics" Knowledge Competition

(1) A = _ _ _ _, B = _ _ _ _ _ in the frequency distribution table,

⑵ Supplementary frequency distribution histogram;

(3) Students with grades above 69.5 will win the first prize or the second prize. First prize award 15 exercise book and scholarship 50 yuan, second prize award 10 exercise book and bonus 30 yuan. It is understood that these students have obtained 335 exercise books. Please find out the bonus they won.

(The full mark of this question is 10) As shown in the figure, in the isosceles trapezoid ABCD, ∠ C = 60, AD∨BC, AD=DC, E and F are on the extension lines of AD and DC respectively, and DE=CF, AF and BE intersect at point P ... (1) Verification: AF.

5] Find the degree of ∠BPF.