1, the quality of an egg, the thickness of a piece of paper in the textbook, and the time for an eraser to fall from the table to the ground is about
A.60g、0.8mm、0.5sB. 10g、80μm、5s；
C.60g、80μm、0.5sD. 10g、0.8mm、5s .
Xiao Liang bought an iron can with a glass bottle from the supermarket. He tried to open the bottle cap, but he couldn't unscrew it. Liang Xiao's brother gently pried a few times along the edge of the bottle cap with a screwdriver and then unscrewed the bottle cap. This is mainly because it is possible to pry open the bottle cap with a screwdriver
A. increase the diameter of the bottle cap and reduce the pressure of the side wall of the bottle cap on the bottle.
B, reduce the contact area between the bottle cap and the bottle mouth.
C, reduce the pressure difference of gas inside and outside the bottle.
D because one side of the cover is pried open, the pressure on the other side of the cover increases.
3, noise control is one of the main projects of urban environmental protection, the following measures can't weaken the noise is ()
A. it is forbidden for motor vehicles to whistle in urban areas. Plant grass and trees on both sides of the city streets.
C, installing a muffler on the automobile exhaust pipe d, and controlling the automobile exhaust emission index.
4. As shown in figure 1, the lid of the indoor trash can is closed at ordinary times to prevent the garbage from emitting peculiar smell. When in use, the lid is opened by stepping on it with your foot. According to the structural schematic diagram of the indoor trash can, it can be determined that
A. There is only one lever in the bucket, which is a labor-saving lever.
There is only one lever in the bucket, and it is a laborious lever.
C. There are two levers in the bucket, both of which are labor-saving levers.
D. There are two levers in the bucket, one is labor-saving lever and the other is laborious lever.
Figure 1 Figure 2 Figure 3
5. As shown in Figure 2, after the switch is closed, when the slider P of the sliding rheostat slides to the right.
A. current means decrease and voltage means increase. B. The current means decreasing, and the voltage means keeping the same.
C. Current means bigger, and voltage means bigger. D. The current means bigger, and the voltage means smaller.
6. there are two circuit elements a and b. The relationship between the current flowing through the element and the voltage across the element is shown in fig. 3 (A). Put it on.
Series connection in the circuit, as shown in Figure 3 (b). Close the switch S, and the ammeter indicates 0. The power supply voltage and electric power of elements 4A and b are respectively
A.2.0V 0.8 W B. 2.5V 1.0W
C.4.5 volts 1.0 watts
7. Stand the luminous stick with a height of 2 cm in front of the convex lens with a focal length of 5 cm, and an image with a height of 4 cm will be formed on the screen behind the convex lens. The distance between the object and the convex lens may be ().
A.7.5 cm B. 12.5 cm
C.4.5 cm D. 10 cm
8. We used a variety of scientific research methods in junior high school physics experiment exploration. In the next four inquiry experiments, the two research methods used are the same.
A. Explore what factors are related to the magnitude of friction. B. Explore the imaging characteristics of flat mirrors.
C. explore the relationship between current and voltage on resistor d and explore the balance condition of lever.
9. Among the following match line options, the correct option is
A. Physical quantities and their units B. Common instruments and their manufacturing principles
Heat value densimeter expands when heated and contracts when cooled.
Force kw? Thermometer electromagnetic induction
Floating conditions for live operation of J/kg generator
C. Scientists and their Contributions D. Physical knowledge and natural phenomena or real life
Newton-Joule law diffusion lens for correcting vision
Joule's law of inertia refracts the palm of your hand.
Amperometric determination of aroma outside the flowering wall under the combined action of air pressure and force.
II. Fill in the blanks (***20 points, 65438+ 0 points per grid)
10. On weekends, Xiao Wang drove out for an outing and moved from south to north. At this time, a car also flew past him from south to north. If you take this car as a reference, Xiao Wang is in the opposite direction. As shown in Figure 4, A and B are the tachometer and speedometer on the dashboard of the car respectively, and there is also an odometer on the speedometer to show the total mileage of the car. From A, we can see that the engine speed of the car is r/min at this time, and from B, we can know that the current speed of the car is 1.2h if the car is driving at this speed, and the odometer shows km.
Figure 4 Figure 5
1 1. Align a paper tube between the flames of two candles and blow gently. It turns out that the vertical candle flame will move closer to the middle. As shown in Figure 5, it shows that the greater the gas velocity, the smaller the position _ _ _ _.
12, many seemingly different phenomena in life often have internal relations. Analyze the following four situations, take two situations as a group, find out the physical laws revealed by them, and fill in the table.
A. Push the flying football out with your head, and your head hurts a little.
B. after the arrow is shot by the bow, it can continue to fly in the air.
C the car slows down after braking, but it can't stop immediately.
D. Lift the bucket hard, and your arm feels pulled down.
The selected example is the same as the physical law revealed.
and
13, "compass" is one of the four great inventions in China. This great invention has important practical value in navigation, exploration and military affairs. A compass can point out the direction because it is influenced by a magnetic field. When the compass is at rest, the direction of the North Pole is near the geographical pole.
14, as shown in Figure 6, is a schematic diagram for explaining the structure of atoms and nuclei. The information provided by this diagram shows that atoms are composed of inner and outer nuclei; The finer structure of protons and neutrons in the nucleus (fill in "Yes" or "No").
Figure 6 Figure 7
15. As shown in Figure 7, the object lifted to 2N is pulled at a uniform speed in the vertical direction with a pulling force of 1.2N, and it takes 4s for the object to rise to 0.1m.. (1) In this process, the power of pulling force is W, and the mechanical efficiency of moving pulley is. (2) Increase the weight of the object by 2N, assuming that the moving pulley can always work normally, in this process, its mechanical efficiency will be. (Select "Increase", "Reduce" or "No Change")
16, new energy and ecological environment protection are two hot spots that people pay attention to in this century. In recent years, street lamps as shown in Figure 8 have been used in some areas of China. This device can convert _ _ _ _ _ energy into electric energy, and they all belong to energy sources (fill in "renewable" or "non-renewable"). The use of mobile phones to transmit information brings convenience to people, but also harms human health due to radiation, so it is necessary to use mobile phones scientifically.
Figure 8 Figure 9
17. As shown in Figure 9, there is a three hole socket, in which the wires of the jack are connected to the outdoor ground. Please connect the symbol e representing the earth in this jack with a line. If the wire in this socket is broken, you can use this socket to turn the washing machine, but the problem is _ _ _ _ _ _ _ _ _ _.
Iii. Drawing and short answer questions (*** 15, 18, 3, 19, 2, 20, 4 and 2 1 6).
18. As shown in figure 10, the plane mirror is placed horizontally and the light is 30? The angle is on the plane mirror. Please draw the reflected light in the picture and mark the reflection angle.
Figure 10 Figure 1 1
19, as shown in figure 1 1, the fish in the water spit out a string of bubbles, and the bubbles are getting faster and faster in the process of rising. The bigger bubble has drawn its gravity diagram, please draw its buoyancy diagram.
20. One day in the winter vacation, Xiaojie and his father went out and suddenly found that the front window of the car was covered with a layer of fog, and the road ahead could not be seen clearly. Xiaojie was worried about driving safety when he saw his father turn on the air conditioner switch and blow warm air on the glass. Soon the fog on the glass disappeared. Please use physical knowledge to explain the process of fog generation and elimination.
2 1. Man's understanding and utilization of fire has changed the world and himself. It can be said that the history of human civilization is the history of the use of fire. If you are in distant ancient times, how can you get fire? Please write three ways to obtain kindling, and state the physical principle of application.
Method 1: Principle:
Method 2: Principle:
Method 3: Principle:
4. Ask questions (***20 points, 2 points for the 22nd question, 6 points for the 23rd question, 7 points for the 24th question and 5 points for the 25th question).
22. Playing basketball is the favorite sport of middle school students. Please put forward a question related to physical knowledge according to the structure of basketball and the process of playing, and give a simple answer.
For example: Question: Why can basketball still be in air movement after being thrown?
A: It is inertia that keeps it moving.
Question:
Short answer:
23. We often have to climb stairs. Do you know how powerful it is to climb stairs? Xiaoli wants to measure the strength of Xiaojun's classmates climbing stairs.
(1), the equipment required for measurement are:
(2) The measurement steps designed by Xiao Li are as follows, among which the redundant ones are
A, measure the gravity of Xiaojun's classmate
B, measure the total length of the stairs
C. Measure the vertical height from the first floor to the third floor.
D, measuring the time for Xiaojun to climb the stairs
E, calculate the strength of Xiaojun when climbing stairs.
(3) Please help Xiaoli design an experimental record form.
24. Xiaoming is going to do the experiment of "measuring the power of small light bulbs". Please follow Xiao Ming while thinking about the experiment and answer the following questions one by one.
(1) Please draw the experimental circuit diagram in the box of 12.
(2) Xiao Ming just connected the last wire and immediately saw the light from the light bulb. Xiaohua, who was watching, was surprised and reminded Xiaoming that there was something wrong with the experiment. Xiao Ming thought, there is no problem with my experimental connection! Please help Xiao Ming find out two improper operations in the experiment: ① _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; ②_______________________。
(3) The rated voltage of Xiaoming's light bulb is 2.5V when it normally glows, and the ammeter reading is as shown in figure 13, and the rated power of this light bulb is _ _ _ _ _ _ _ _ _ W.
Figure 12 Figure 13 Figure 14
(4) After the experiment, Xiao Ming compared the experiment of measuring the actual power of light bulb with the experiment of measuring the resistance of fixed resistor, and found that the two experiments have many similarities and differences. Please write down the differences:
___________________________________________________________________ ______。
(5) Xiao Ming made an I-U diagram according to several groups of experimental data for measuring the actual power of light bulbs, as shown in figure 14. It is found that the graph is not a straight line, indicating that the current of the bulb is not proportional to the voltage. Cheng Yue is very puzzled. Please help him analyze the reason.
.
25. Ding Ding and Dong Dong designed the experiment of "Exploring the current relationship in parallel circuits" respectively. Their experimental circuit diagrams and data records are shown in figure 15.
Figure 15
(1) According to their experimental data, we can get the sum of the total current and each branch current in the parallel circuit (fill in "greater than", "less than" or "equal to").
(2) According to his experimental data, Dong Dong thinks that the currents of each branch in the parallel circuit must be equal, because the relationship between the two resistors he chose is. (fill in ">", "
(3) How do you think Tintin and Dongdong's experiments should be improved?
Ding Ding:
Winter and winter:
V. Calculation problem (*** 15, item 26, item 4, item 27, item 5, item 28, item 6).
26. Xiaoming experimented with a bottle filled with pure water and a sponge placed on a horizontal table to study the "factors affecting the pressure effect", as shown in figure 16. Doing it, Xiao Ming thought about how much pressure a bottle of pure water can produce to make the sponge sink so obviously. So he began to try to calculate. He found from the trademark paper that the "net content" of this bottle of water is 600mL. The same empty bottle is really light, and gravity can be ignored; It is also measured that the bottom area of the bottle is 35cm2 and the cover area is 7 cm2. According to the data collected by Xiao Ming, please calculate:
(1) What is the net weight of this bottle of pure water? (g = 10 Newton/kg)
(2) What is the pressure on the sponge when the bottle is placed upright?
(3) What method can be used to make the sponge bear the same pressure when the bottle is inverted?
Figure 16
27. Xiao Fang and her mother went to the mall to buy an electric water heater, and the salesman recommended a "quick-heating and variable-capacity" water heater to them. This electric water heater has two heating modes: when a small amount of water is used, the "half box heating" mode is used, and only the upper heating rod is used to heat the upper half box of water; When a large amount of hot water is needed, the water heater will start the "full gallbladder heating" mode and use the upper and lower heating rods to heat at the same time. The following table is the nameplate of the water heater, please answer according to the relevant data.
Product name: rated pressure, heating power, distribution quality and capacity, maximum heating capacity
Thermal temperature efficiency
××
Water heater 0.8MPa half gallbladder 1000W
Full gallbladder 2000W 30kg half gallbladder 40L
Gallbladder adjustment 80L 80℃ 80%%
(1) When using the "full tank heating" mode, please judge the circuit connection mode of two electric heating rods.
(2) When the electric water heater is used in the "full tank heating" mode, if the water temperature is raised from 20℃ to 60℃, how much heat does the water need to absorb? How long does the electric water heater need to be heated?
28. in the circuit shown in fig. 17, R 1 and R 2 are constant resistors, and the lamp l is marked with the words "16V and 4W", and the power supply voltage is unchanged. (1) Close the switches S, S 1, S 2. At this time, the indicator of the ammeter is 0.35A, and the lamp L 1 can just emit light normally. Find the size of the resistor R 1. ⑵ Turn on the switch S, turn off the switches S 1 and S 2, and the voltmeter indicates a change of 3.2V compared with (1). Find the electric power consumed by resistor R 2 at this time (filament resistance is constant).
Figure 17
A, multiple-choice questions (***20 points, you think the correct answer number is filled in the brackets after the question. Question 1 ~ 7, each question has only one correct answer, and each question has 2 points; Questions 8 and 9, each with one or more correct answers, each with 3 points. 3 points for correct selection, 0 points for correct selection but incomplete selection 1 point, 0 points for non-selection, multi-selection or wrong selection. )
1、 2、 3、 4、 5、 6、 7、 8、 9、
C C D D A C A AC ABD
II. Fill in the blanks (***20 points, 65438+ 0 points per grid)
10, south 3000 80km/h 13697.8
1 1, pressure
12、
Betty 13
14, electron
15, up by 0.0683.3%.
16, the sun (or light; Or machinery; Or wind) renewable electromagnetic waves.
17、
This jack has a safety function. If it is disconnected from the earth, once the insulation between the electrical appliance shell and the power supply live wire is destroyed, it is easy to cause an electric shock accident.
Iii. Drawing and short answer questions (*** 15, 18, 3, 19, 2, 20, 4 and 2 1 6).
18、 19、
20、
2 1, reasonable.
4. Ask questions (***20 points, 2 points for the 22nd question, 6 points for the 23rd question, 7 points for the 24th question and 5 points for the 25th question).
22, omitted
23、
24.( 1) draft
(2)① The switch is closed when wiring; ② The resistance value of the sliding rheostat in the access circuit is not adjusted to the maximum value.
(3)0.75
(4)① The purpose of measuring power and resistance is different. ② Different according to physical principles (power measurement P=UI, resistance measurement R=U/I). (3) It is not necessary to measure the average actual power for many times, but it is necessary to measure the average resistance for many times to reduce the error. Note: As long as you answer one question correctly, you can get full marks. Other reasonable answers can also get full marks. (5) The resistance of filament changes (increases) with the increase of temperature.
25、
V. Calculation problem (*** 15, item 26, item 4, item 27, item 5, item 28, item 6).
26. (1) 6n (2)1.7×103pa (3) is omitted.
27.( 1) parallel connection (2)1.33x107j8400s
28、⑴ 16ω⑵0.64 w