How to solve physics and chemistry problems in the senior high school entrance examination?

1. Multiple choice questions (this topic is entitled ***7 small questions, with 3 points for each small question, ***2 1 point). Only one of the four options listed in each small question is correct. Please write the letter of the correct option in brackets after the question.

1. Among the following practices, () is the most beneficial to environmental protection.

A. replacing coal and oil with natural gas. B. Waste batteries are buried together with other wastes.

C. replacing hydropower with nuclear energy D. developing solar energy to replace coal and natural gas for heating.

2. The following electrical appliances, the use of electromagnetic waves is ().

A. electric fan B. mobile phone C. refrigerator D. hair dryer

3. As shown in figure 1, it is a concave road design, which can play a role in controlling the environmental impact of noise generated by automobile driving. Which of the following methods is adopted in this design to reduce noise ()

A. attenuation at the sound source

B. weaken in the process of transmission

C. Weakening of human ears

D. None of the above options are correct.

4. In the early morning of summer, some fog often appears on the river, and the change of state in this phenomenon is ()

A. steam sublimation B. steam liquefaction

C. steam curing D. steam condensation

5. Under normal circumstances, all belong to the conductor is ().

A. sea water dry wood for human body B. rubber nail ceramics

C. Coin graphite copper block D. Mercury plastic hydrochloric acid

6. The four-stroke schematic diagram of a single-cylinder four-stroke internal combustion engine is shown in Figure 2. The following is correct about the order of four strokes in a working cycle of this internal combustion engine ()

A.c，D，B，A，B，D，A，c。

C.b., a, d and C.

7. As shown in Figure 3, three uniform solid iron columns with the same material but different thicknesses and lengths are vertically placed on the horizontal ground, and the one with less pressure on the ground is ().

A. Armored iron column

B. Iron column

C. propylene tower

D. unable to determine

2. Fill in the blanks (this topic is entitled ***7 small questions, with 3 points for each small question, ***2 1 point). Please fill in the correct answers to the following questions on the line.

8. When a rocket is launched, the _ _ _ _ _ _ _ energy of fuel combustion can be converted into the _ _ _ _ _ _ _ energy of the rocket. When the Shenzhou VI spacecraft runs in space, the solar energy absorbed by the solar panels is converted into _ _ _ _ _ _ _ _ _.

9. Aerial photographers take pictures of the city from high altitude. If the focal length of the camera lens used is 80 mm, the distance between the film and the lens should be 80 mm (fill in "greater than" or "less than"), and the obtained image is _ _ _ _ (fill in "upside down" or "upright").

10. The length of the solenoid in Figure 4 A is _ _ _ _ _ cm; The stopwatch in figure 4 B reads _ _ _ _ _ s；; Fig. 4 the c reading of the spring dynamometer is _ _ _ _ n.

1 1. The specific heat capacity of water is 4.2× 103 J/(kg℃ kg℃). If half of 2 kg of water is poured out, the specific heat capacity of the remaining water is _ _ j/(kg℃); After water freezes, its specific heat capacity will be _ _ _ _ _ (fill in "change" or "unchanged"); When the initial temperature is 20℃ and the water with the mass of 1 kg absorbs 2. 1× 105 J, the temperature will rise to _ _ _ _ _ _ _.

12. As shown in Figure 5, when you turn on the power switch, you will find that the north pole of the small magnetic needle is deflected to _ _ _ _ _ (fill in "left" or "right"), indicating that there is _ _ _ _ _ _ _ around the energized solenoid; At the same time, it is found that the movable solenoids A and B are mutually _ _ _ _ _ _ _ (fill in "near" or "far").

13. When the three electrical instruments are in normal use, as shown in Figure 6, the ammeter reading is _ _ _ _ _ A, the voltmeter reading is _ _ _ _ _ _ _ _ V, and the watt-hour meter reading is _ _ _ _ _ _ _ _ kW h.

14. Use the pulley block shown in Figure 7 to lift an object with a weight of G= 12 N by 20 cm at a uniform speed. The tension used is F=5 N, the useful work done is _ _ _ _ j, and the mechanical efficiency is _ _ _ _ _. When lifting the weight of 18 N instead, the mechanical efficiency of the pulley block is _ _ _ _ _ (ignoring the friction resistance).

Three, painting questions (7 points)

15.

(1) In Figure 8, a beam of light AO is obliquely projected from the air to the water surface, and its roughly refracted light (and normal line) is drawn.

(2) In Figure 9, the switch and the light bulb are correctly connected to the home circuit through contact wires instead of wires.

(3) In the picture 10, the solid iron ball sinks in the water. Draw the gravity and buoyancy diagram of the ball at this time.

Fourth, the experimental questions (this big question ***3 small questions, *** 19 points)

16.(6 points) (1) As shown in figure 1 1, it is an experiment to measure the current in the circuit with an ammeter, in which the ammeter measures the current passing through _ _ _ _ _ _ (fill in "A resistor", "B resistor" or "main circuit"). In order to measure the voltage across resistor B, a line is used instead of a wire, and the voltmeter is correctly connected to the circuit.

(2) Figure 12 A shows a student measuring the temperature of boiling water when doing the experiment of "observing the boiling of water". Due to an operational error, he found that the thermometer reading was greater than 100℃, and his error was _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. After correcting the mistake, he observed that when the water was boiling, the thermometer reading was as shown in figure 12B, and the boiling point of water was _ _ _ _ _ _ _℃

(3) As shown in Figure 13, when using a horizontal desktop, it is found that the light beam is slightly tilted to the right. To adjust it to a balanced state, please write down the necessary steps: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

17.(6 points) Xiao Ming and other students use the equipment around them for experimental exploration. They first put a thin plastic straw on the nail, then wound a thin metal wire around the thin plastic straw to make a solenoid, and fixed the device on the bracket, as shown in figure 14.

(1) Among the following physical phenomena, the experimental device shown in Figure 14 can be used to explore _ _ _ _ _ _ _ _ (fill in the serial number).

A. Force on charged conductor in magnetic field B. Electromagnetic induction

C. electromagnetics

(2) The experimental device shown in Figure 14 can explore the relationship between the magnetic field intensity of the solenoid with iron core and _ _ _ _ _.

(3) In the experiment, Xiao Ming turned off the switch and found that the nail could not absorb the pin. They moved the rheostat slider P from the A end to the B end, and the ammeter reading gradually became larger, but the needle was still not sucked. It is found that there are enough turns in the winding core, so one possible reason for this phenomenon is: _ _ _ _ _ _ _ _ _ _ _.

18.(7 points) Is the sliding friction related to pressure and contact area? Please use the following experimental equipment to explore: a spring dynamometer with large enough range, weighing 2 N, two identical cuboid blocks (with hooks) and a long board.

(1) Write the experimental steps:

a._______________________________________________________________;

b._______________________________________________________________;

c._______________________________________________________________。

(2) Fill in the missing contents on the horizontal line of the following experimental record.

_ _ _ _ _ _ _ _ _ _ _ spring dynamometer reading /N sliding friction /N

______________

______________

______________

V. Calculation problem (this big problem is ***2 small problems, *** 13 points)

19.(6 points) A car with a mass of 3000 kg runs at a constant speed along the Panshan Highway with a length of 5.4 km. When it travels from the foot of the mountain to the top of the mountain with a height of 0.5 km, it takes 15 min. The traction of the car engine is 4000 n. Q:

(1) speed;

(2) the work done by the traction of the automobile engine;

(3) Traction power of automobile engine.

20.(7 points) As shown in figure 15, after a small light bulb L of "3V 1.5W" is connected in series with a resistor R of 0.6 Ω, the small light bulb normally emits light (the filament resistance value of the light bulb does not change with temperature). Q:

(1) small bulb resistance rl;

(2) the voltage across the resistor r;

(3) If the light bulb is directly connected to the power supply, the light bulb will not be burnt out. What is the actual power of the light bulb at this time?

Six, the comprehensive ability problem (this big topic ***3 small questions, *** 19 points)

2 1.(6 points) At present, there are four main ways to treat urban garbage in the world: classified recovery, landfill, composting and incineration. China/KLOC-large and medium-sized cities with a population of more than 0/10,000 have basically reached the maturity standard of garbage power generation stipulated by the United Nations Environment Organization (UNEP). Up to now, nearly 30 waste incineration power plants have been built in many cities in China.

(1) It is reported that in 2009, a city in China will build the largest garbage incineration power plant in China and the third in the world, and the daily incineration of domestic garbage will reach 3000 t (tons). If the garbage is completely burned, the heat released every day is Q =1.5×10/3 j. If 2 1.6% of the released energy is converted into electric energy, try to calculate how many kWh of electric energy this garbage incineration power plant generates every day.

(2) If each household lights up three 40 W lamps for 5 h every day, how many households can use the electricity generated by the waste incineration power plant for lighting every day?

(3) What are the benefits of building a garbage incineration power plant? Please write down two examples:

_________________________________________________________________

22.(6 points) In the evening, Xiao Wu was enjoying the symphony from the stereo at home when the power went out suddenly. He lit the candle and put it in front of the speaker. After a while, the electricity was turned on and the symphony began again. Xiao Wu found that the candle in front of the speaker was swaying from the mirror hanging on the wall. Careful observation also found that when the volume of the speaker suddenly increased, the flickering of the candle flame became more obvious.

(1) The candle flame is not affected by the wind. Further exploration shows that the closer the candle is to the speaker, the more obvious the flickering of the candle flame, which can be determined to be caused by the influence of _ _ _ _ _ _ _.

(2) The candle he saw in the mirror is a _ _ _ _ _ _ _ _ _ (fill in "real" or "virtual") image formed after _ _ _ _.

(3) When the candle is closer to the sound box, the size of the candle in the mirror will be _ _ _ _ _ _ _. (Fill in "bigger", "smaller" or "unchanged")

(4) In the above phenomenon, besides loudness knowledge, there are related sound knowledge (write two examples):

________________________________________________________________

23.(7 points) When Xiao Liu used a water gun to help his father wash the car, he found that the horizontal distance of the water jet was different when the water gun was facing different angles or the speed of the water jet was different. Therefore, he made the following inquiry (as shown in figure 16), and the corresponding data records are shown in table 1 and table 2:

Table 1:

Angle between water gun and horizontal line Horizontal distance of water injection/meter

10 0.5

30 1.3

45 1.5

60 1.3

80 0.5

Table 2:

Jet speed of water gun, horizontal distance of water jet/meter

Smaller 0.5

Slightly larger 1

Larger 1.5

Bigger 2

The analysis of the above inquiry is as follows:

(1) The water leaving the nozzle can still move forward in the air, which is due to _ _ _ _ _ _ _ _.

(2) Keep _ _ _ _ _ _ _ _ _ _ _ _ unchanged for the time being. Draw a conclusion: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(3) During the second inquiry, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ shall remain unchanged. Draw a conclusion: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(4) According to the conclusion of inquiry 1, give an example of practical application: _ _ _ _ _ _ _ _ _ _.

Reference answer

1.D

The analysis of energy and environmental protection has always been the main problem that puzzles modern society. Coal, oil and its by-products are the main energy sources, but in the process of use, a large amount of waste gas, such as SO2 and nitrogen oxides, will be produced, which will pollute the environment. Natural gas is more abundant in the combustion process, but there is still a small amount of waste gas. Waste batteries are difficult to degrade, and even if buried, they will pollute the soil. Hydraulic resources are a kind of clean and environment-friendly energy. Solar energy is inexhaustible and has no impact on the environment. Although it is inefficient and affected by the weather at present, it is still the most favorable way to protect the environment.

2.B

The electrical appliances in A, C and D all work by electricity, while the mobile phone works by the vibration of electromagnetic waves to spread sound waves, so B is selected.

3.B

It is analyzed that the noise generated by the automobile is reflected repeatedly by the groove in the propagation process, and the energy is gradually reduced.

4.B

The temperature difference between day and night in summer is large, and a large amount of water vapor evaporated into the air during the day liquefies after the temperature drops in the morning, forming small water droplets, that is, fog. Similar problems are peeling popsicle paper in summer, and there is a layer of white fog around the popsicle; Boiling water, there is a layer of white fog above the pot after the lid is opened, all of which are caused by the liquefaction of small water droplets by steam. At present, most of the "white fog" problems we encounter are caused by the liquefaction of water vapor when it meets cold.

5.C

Analysis should remember clearly some common conductors and insulators in books. Metal is a conductor, and coins are alloys and conductors. The dry wood in item A is an insulator, and the rubber and ceramics in item B are insulators.

6.B

The analysis of this problem is mainly to investigate the stroke and related actions of internal combustion engine.

7.A

By analyzing this problem, we can understand the definition of stress. As a cylinder, we can know that the pressure of a regular cuboid on the horizontal plane is only related to its material and height, and has nothing to do with the size of the bottom area.

8. Internal (or thermal) power (or mechanical) power (3 points)

9. Above handstand (3 points)

10.2. 10; 20 1.6(3 points)

11.4.2×103 changes by 70(3 points)

12. Left magnetic field approach (3 points)

13.0.36 12 757.8 (3 points)

14.2.4 80% 85.7% (or 86%)(3 points)

15.

(1) as shown in figure 1(2 points, no points will be deducted for mistakes)

(2) As shown in Figure 2 (2 points, no points will be deducted for mistakes)

(3) See Figure 3 (correctly draw buoyancy 1, gravity 1, and buoyancy is less than gravity 1).

16.(6 points)

The resistance of (1) B is shown in Figure 4(2 points, the first grid 1 min, and the circuit diagram 1 min is correctly connected).

(2) The glass bulb of the thermometer touches the bottom 99 of the container (2 points, 1 point/space)

(3) Move the stray code to the zero scale at the left end of the scale; At the same time, adjust the balance nut of the cross beam until the cross beam is balanced (scoring description: 2 points will be deducted for all answers, and no points will be deducted for incomplete or wrong answers).

17.(6 points)

(1)C(2 o'clock)

(2) Current scale (2 points)

(3) The thin iron wire has no insulation and turns are short-circuited; Or the thin iron wire touches both ends of the nail; Or nails are not made of steel. The current is too small, the magnetism is too weak, and the pin is too far. (2 points)

(Scoring description: As long as the explanation is reasonable, you can get 2 points. )

18.(7 points) Experimental steps:

(1) a. Put a wooden board flat on a long wooden board, pull it horizontally with a spring dynamometer at a uniform speed, read the indicated value of the spring dynamometer and record it in the table below (1).

B put a piece of wood on the edge of a long board, use the same square farad block, and write down the corresponding instructions (1).

C. Stack two pieces of wood together, lay them flat on a long board, and then use the same square farad block to record the corresponding instructions (1).

(Note: The order of the three steps can be reversed. If it is written in two steps, it is correct as long as it can express that it has gone through three operation processes. )

(2)

Pressure of wood block on board /N

A piece of wood lies flat on the board.

A piece of wood is placed on the edge of the board.

Two pieces of wood are folded and laid flat on the board.

(Scoring description: 4 points, each space 1 point. As long as it can express that one piece is flat, the other piece is horizontal and the other piece is stacked, it is all correct. )

19.(6 points) Solution:

(1)(2 points)

or

(2) w = fs = 4000 n× 5.4×103m = 2.16×107j (2 points).

(3)(2 points)

Answer: (1) The speed is 6m/s;

(2) The work done by the traction of the automobile engine is 2.16×107j;

(3) The traction power of the automobile engine is 2.4×104 W.

20.(7 points) Solution:

(1) When the small light bulb emits light normally, UL = 3 V.

∫p = international unit ∴( 1 points)

∫∴( 1 points)

(Note: If the correct answer is obtained by other formulas, it is also 2 points. )

(2)∵

∴ ur = IR r = 0.5a× 0.6ω = 0.3v (2 points)

(3)U total =UL+UR=3 V+0.3 V=3.3 V( 1 point)

( 1)

Preal = ireal ureal = 0.55a× 3.3v =1.815w (1min).

Answer: (1) The resistance of the small bulb is 6 Ω;

(2) The voltage across the resistor is 0.3v；; ;

(3) The actual power of the small bulb is1.815 W. ..

2 1.(6 points)

( 1)W = 2 1.6%× 1.5× 10 13j = 3.24× 10 12j

= 9× 105 kwh (2 points)

A: The daily output of this garbage incineration power plant is 9×105 kW h h.

(2) The daily lighting power consumption of a family:

w = Pt = 3×40w×5h = 0.6 kW·h

Number of available families:

(1) (2 points)

Answer: It can be used for 1.5× 106 household lighting.

(3) For example: energy recovery; Conducive to environmental protection. (or conducive to saving land resources; Or a high degree of waste reduction) (2 points, other reasonable answers can be given)

22.(6 points)

(1) Sound waves (or symphony sounds, or speakers and stereos) (1 min)

(2) the reflection of light (or plane mirror imaging, or mirror reflection) is virtual (2 points)

(3) unchanged (1)

(4) Example: Sound is produced by object vibration; Sound can transmit energy; Or sound can travel in the air. (2 points. The correct answer is 1. Answer: timbre, timbre, loudness and related contents are not scored)

23.(7 points)

(1) Water has inertia (1)

(2) Water spraying speed When the water spraying speed is constant, the angle between the water gun and the horizontal line gradually increases, and the horizontal distance of water spraying first increases and then decreases. When the included angle is 45, the horizontal distance is the largest. (Per grid 1 minute, ***2 points)

(Scoring Note: If the conclusion fails to answer "When the included angle is 45, the horizontal distance of shot put is the largest", you can also score. )

(3) Angle between the water gun and the horizontal line When the angle between the water gun and the horizontal line is constant, the speed of spraying water increases gradually and the horizontal distance of spraying water also increases gradually. (Per grid 1 minute, ***2 points)

(4) For example: physical education class's javelin throw (or throwing solid ball) must be thrown at a specific angle in order to throw it far (2 points).

Shanxi province junior high school graduation exam in 2006 (new curriculum standard)

Physical principle

1. Multiple choice questions (only one of the following questions meets the meaning of the question, please fill in the letter label in the brackets after the question, with 3 points for each question and 30 points for * * *).

1. Among the following objects, the one that works by electromagnetic waves is ().

A. "B-ultrasound" detector B. Microwave oven C. Electromagnetic crane D. Rice cooker

2. The following state changes are endothermic ()

A.in spring, the frozen river melts. B. In summer, open the refrigerator door and "white gas" comes out.

C. In autumn, dew appears on plants; In winter, frost forms on the ground.

3. The following circuit connection statement is correct ()

A. The lights on the road are on and off at the same time. They are connected in series.

B the lighting lamp in the household circuit is connected in series with the socket.

C. In the household circuit, the TV and the lighting lamp are connected in parallel.

D. A cold and hot hair dryer for haircut, in which a motor and an electric heating wire are connected in series.

The first phase detector of China Chang 'e Project is scheduled to be launched in April next year. If you are lucky enough to be the first astronaut to land on the moon in the history of China, what do you think may happen on the moon?

A. land with a parachute. You can easily lift 50 kilograms above your head.

C.you will see the blue sky. D. you can hear the sound of electric cars running.

5. The following statement about sound phenomenon is true ()

A. When the sounding tuning fork touches the water surface, the water surface will splash, indicating that sound can spread in water.

B. Knock on one end of a long enough iron pipe, and people at the other end will hear it twice, indicating that the sound will be reflected.

The medical application of ultrasonic lithotripsy shows that sound can transmit information.

D. The greater the drum beat, the louder the sound, indicating that the greater the amplitude, the greater the loudness.

6. Among the following options, the group that is all insulators is ().

A. dry stick, human B. glass, salt water C. ceramics, metal D. rubber, plastic

7. In the four scenarios of figure 1, () can be explained by inertial knowledge.

When Xiao Ming took a bath at home, he contacted and applied a lot of physical knowledge. He summed up several items, but one was wrong ()

An electric water heater is a device that converts internal energy into electric energy.

B. The hot water soaked the body and felt warm, and the heat was transferred between the hot water and the skin.

C a layer of water mist is often attached to the mirror of the bathroom, which is a liquefaction phenomenon.

D. When using shower gel, the room is full of fragrance, indicating that molecules are constantly moving.

9. Figure 2 is a model camera made by a classmate. One end of the paper tube A is covered with a layer of translucent paper, and one end of the paper tube B is embedded with a convex lens. These two paper tubes are nested together to form a model camera. In order to get a clear image at the A end, it is necessary to adjust the distance between A and B. At this time ()

A. Look into the barrel with your eyes toward the B end to see if the image is clear.

B. If you see the nearby scenery clearly and then look at the distant scenery, you should pull B outward to increase the distance between A and B..

C.A end should face the bright outdoor and B end should face the dark indoor, otherwise you can't see clearly.

D.B end should face the bright outdoor and A end should face the dark indoor, otherwise it is not clear.

10. The inclined plane shown in Figure 3 is 3 m long and 1 m high. Workers use a force of 400 N to push the box weighing 840 N onto the car along the inclined plane. The following statement is true ()

A. 400 J of useful work and 840 J of total work.

B. useful work 840 J, extra work 400 J.

C. total work 1200 J, with an efficiency of 70%.

D. useful work 400 J, efficiency 70%.

II. Fill in the blanks (every space 1 minute, *** 14)

1 1. As shown in Figure 4, an object is pulled by a spring dynamometer to make a uniform linear motion in the horizontal direction. The spring dynamometer indicates _ _ _ _ _ _ _ n, and the friction force of the object in the horizontal direction is _ _ _ _ _ _ _ n.

12. Measure the mass of the object with the adjusted balance. When the beam is in a balanced state, the position of the additional weight and the traveling code is shown in Figure 5, and the mass of the object is _ _ _ _ _ _ _ _ _ g；; If the weight is worn, the weighed mass is higher than the object mass. (Fill in "big" and "small").

13. There are many poems describing the phenomenon of light in ancient poetry. "Shallow pool" refers to the phenomenon of light. "The pool reflects the bright moon" refers to the phenomenon of light.

14. When the weight of an object is 20 N, when it is completely submerged in water, the weight of the water it displaces is10 N. At this time, the buoyancy it receives is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

15. The internal combustion engine is a machine that converts internal energy into _ _ _ _ _ _ energy; As shown in Figure 6, it is the _ _ _ _ _ stroke of the internal combustion engine.

16. When water with a mass of 1 kg and a temperature of 20℃ is added to boil, the heat absorbed is _ _ _ _ _ _ _ j.

[c water = 4.2×103j/(kg℃); The air pressure is 1 standard atmospheric pressure]

17. the disk of Xiaoming watt-hour meter is marked with the words "3000r/kw h". If this watt-hour meter is used to measure the electric power of an electrical appliance, the turntable is there.

After 5 minutes and 60 revolutions, the work done by the current is _ _ _ _ kW h = _ _ _ _ J, and the electric power of this appliance is _ _ _ _ _ W.

III. Drawing and short answer questions (18 ~ 20 2, 2 1 4, *** 10)

18.(2 points) As shown in Figure 7, the infrared ray emitted by the remote controller is reflected by the wall MN. Please draw the incident light in the picture and mark the incident angle.

19.(2 points) When the current indicator is 0.26 A, please mark the pointer position indicating the current on the ammeter, as shown in Figure 8, and lead out the lead from the terminal to indicate the range used.

20.(2 points) As shown in Figure 9, when pulling a nail with a claw hammer, the force acts on point A on the hammer handle. Please make a schematic diagram of the minimum power f used when pulling nails. (Continue to draw traces)

2 1.(4 points) In recent years, many cities have strengthened the improvement and beautification of the environment, cleaned and dredged rivers, developed artificial lakes, and greatly increased the green area. Would you please talk about the benefits of doing so to adjust the temperature from the perspective of physical knowledge?

Four, experiment and inquiry questions (22 questions 14, 23 questions 10, ***24)

22. Read the following materials:

When the platform skier appeared at the top of the runway, the eyes of the audience were fixed on him.

The athlete slid down from a height rapidly, and when he was about to reach the bottom of the runway, his speed had reached 100 km per hour. At this time, his knees were bent, and he pushed hard and jumped into the air. Then, in order to reduce the influence of air resistance, his upper body leans forward and his arms swing back. His whole body glided forward like an airplane, the biting cold wind whipped his face, and the cedars on both sides quickly passed back. Finally, the snowboard touched the ground steadily, as shown in figure 10, which was a wonderful moment taken by the reporter with his camera.

(1)(8 points) Skiing is not only a sport, but also a science. Please find out the phenomena related to physics from the following materials and tell the corresponding principles, reasons or concepts.

Principles (or principles, concepts) of phenomena related to physics in charts and texts.

When an athlete slides down quickly from a height, the potential energy of gravity is converted into kinetic energy.

1 Relativity between backward flight and stillness of cedars on both sides.

Give it a push.

3 Jump into the air

Like a small plane, it glides forward.

(2)(6 points) Xiao Yu found that whether the athletes can touch the ground stably in the skiing competition is the key factor to score. He guessed that the stability of the athlete when landing may be related to his center of gravity. So he used the scientific inquiry method he learned in physics class to test the conjecture. Kohane found two identical erasers, one vertical; The other piece is laid flat, and 1/5 of the total length is cut off and placed in the lower part (glued). As shown in figure 1 1, when books are placed on horizontal paper at the same time, it is found that the vertically placed eraser always falls off first.

(1) In the process of exploration, Xiao Yu used the same contact area to observe _ _ _ _ to judge the relationship between stability and the height of the center of gravity;

② Through the above research, we can draw the following conclusions: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

③ This conclusion has many applications in production, life and scientific practice. For example.

23.( 1) (4 points) In the experimental class, the teacher took out a circuit board (as shown in figure 12). When the switch S is closed, it is found that the lamp L is not lit, and it has been determined that it is caused by the short circuit or open circuit of the lamp L, which fault needs to be detected. Xiaoyu and her classmates made a detection circuit as shown in figure 13. Turn off the switch S of the faulty circuit and connect M and N to terminals A and B, respectively.

If the detection light is on, the fault is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

If the detection light is not on, the fault is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2)(2 points) The teacher's praise inspired the experimental enthusiasm of the group members. Xiaoyu connected the potentiometer (as shown in figure 14) brought from home to the two points of the detection circuit m and n, and rotated it clockwise, and the light bulb gradually became brighter. Please tell us the connection method as shown in figure 15 (optional "a", "b" or "c").

(3)(4 points) Team members feel the joy of success, and their experimental enthusiasm is even higher. I also want to explore some other electrical experiments. If you are a team member, please use the existing equipment (battery pack, light bulb and wires) and add some electrical equipment commonly used in the experiment. What other electrical experiments can you complete? Complete the following table with reference to the example.

Add the electrical experiment name of the equipment.

Taking small light bulb, voltmeter and switch as examples, the voltage law of series circuit is studied.

1

2

5. Calculation problem (6 points for each small question, *** 12 points. When solving, you must have the necessary text description, formula and calculus steps, and only write the final result.

24.(6 points) As shown in the circuit of figure 16, the power supply voltage is constant, and the word "6V 3W" is marked on the light bulb L. When both S 1 and S2 are closed, the light bulb normally emits light. Q:

(1) filament resistance;

(2) The electric energy consumed by ordinary light bulbs for 20 minutes;

(3) When S 1 is closed and S2 is open, the current through the circuit is 0.2A Please calculate two different physical quantities according to the conditions given in the question. (assuming constant filament resistance)

25.(6 points) As shown in Figure 17, it is a XX car, and the relevant data are listed in the table below.

The car has a mass of 600 kg and a rated power of 40 kW.

The contact area between each tire and the ground is 500 cm3 100 km, and the fuel consumption is 10 L.

The density of gasoline is 0.75× 103 kg/m3. Gasoline price 6.4 yuan/kg.

Q:

(1) What is the ground pressure when the car is stationary on a level ground?

(2) If the fuel consumption is 100 km, how much will it cost?

(3) If the car runs in a straight line at a constant speed with rated power on a horizontal road at a speed of 90 km/h ... Please calculate the work done by traction and the resistance of the car within 10 minute. (g= 10 N/kg, 1 L = 1 decimeter 3)

Reference answer

1.b The analysis of this question requires students to know something about common machinery in life. The instrument in item A works by ultrasonic wave; Item c instrument works by current magnetic effect; The instrument in item D works with current efficiency. Only the microwave oven of item B works by electromagnetic waves. So choose B.

2. An analysis of this question examines students' understanding of absorption and heat release in the change of material state. Students are also required to understand how fog, frost and "white gas" are formed when boiling water in life. The state change in BCD is exothermic, and only the melting in item A is endothermic.

3.c Analysis This question examines the correct connection mode of household appliances-parallel connection, otherwise if one of the appliances has an open circuit fault, all the appliances will not work. Street lamps should be connected in parallel, and the reason why all street lamps will be turned on and off at the same time is because the switch is connected to the main road; In item D, if the motor is connected in series with the heating wire, the hair dryer will not have a cold or hot gear, so the correct answer is C.

The purpose of this question is to examine students' understanding and application of two special points on the moon. First, there is almost no air on the moon, it is a vacuum; Second, the weight of the same object on the moon is one sixth of that on the earth. Because there is no air on the moon, parachutes can't be used normally and sound can't spread in a vacuum. Do you see it? /ca & gt；