I'll choose (there is only one correct answer for each question, 2 points for each question, ***50 points,)
1. The weight of a junior high school student is probably (▲).
A, 4 Niu B, 40 Niu C, 400 Niu D, 4000 Niu
2. Humans have different senses and receptors, and can feel various stimuli and produce different feelings. In the picture below, it is (▲) that feels external stimuli with hearing.
3. Regarding the correspondence between scientific quantity and its unit, the following statement is incorrect (▲).
A, speed, m/s b, force, cattle c, distance, m d, force, kg.
4. When an object is placed on an inclined plane, the gravity diagram on the object is correct (▲).
5. Assuming that the friction between all objects disappears, which of the following phenomena will not happen: (▲)
A, parked on a level road car can't start. B, we can't write with pens.
C. People standing on the ground have no pressure on the ground D. You can push the train with one finger.
6. What people hear is (▲)
A, eardrum b, ossicles c, cochlea d, brain
7. In the next process, the gravitational potential energy of the object increases and the kinetic energy decreases (▲).
A, accelerate the take-off when the rocket takes off. B the paratroopers descend at a constant speed after opening their umbrellas.
C. the basketball rises vertically after being thrown. The car slowed down and drove down the slope.
8. In the darkroom, a beam of white light shines on the green plants through the red glass. You observe that the color of plants is (▲).
A, white b, red c, black d, green
9. Put an electric bell in the glass cover, connect the circuit, and the electric bell rings. When the air in the glass cover is pumped out by the air pump, it will happen (▲).
A, the vibration of the bell stopped. B, I saw the bell vibrating, but I couldn't hear the sound.
C, the bell is louder than before. D, the bell does not vibrate, but can hear the sound.
10. Among the following practices, what increases friction is (▲).
A, reduce the pressure between objects B, make uneven patterns on the soles.
C, add lubricating oil to the ball of the bearing D, and apply some wax to the zipper of the handbag.
1 1. pry the stone with a crowbar, as shown in the figure, the end of the crowbar is easier to take than the middle of the crowbar; This process shows that the role of force is related to which of the following factors (▲)
A, the magnitude of force b, the direction of force c, and the point of force d are all wrong.
12. The most telling fact is that force can change the motion state of an object: (▲)
A, people sit on soft sofas. B, skydivers fall in the air at a constant speed along the vertical direction.
C. press the balloon hard and it will be squashed. D. the football player pushes the flying football back with his head.
13. Which of the following sports belongs to mechanical sports (▲)
A, withered and yellow leaves fall to the ground; b, electric bells are introduced into people's ears; c, the sun shines on the earth; d, peaches bear fruit on peach trees.
14. You will have this experience when swimming in the swimming pool. The shallow water area of the swimming pool looks shallow, but when you step on it, you will feel "empty". This is because the actual depth of the swimming pool is deeper than it looks. The reason is (▲)
A, refraction of light b, reflection of light c, straight-line propagation of light in water d, and change of propagation speed of light.
15. If there is no gravity, the following statement is incorrect (▲).
A, the river can't flow. B, people leave the ground as soon as they jump.
C, the object has no mass D, the water in the cup can't be poured into the mouth.
16. As shown in the figure, AB is the object placed in front of the plane mirror, and A/B/ represents the image of the object in the plane mirror. The correct one in the picture below is (▲).
17. The football player kicks the football into the air (left in the picture below). If air resistance is not considered, the following is the stress diagram of football flying in the air, which is correct (G stands for gravity and F stands for the force of feet on the ball) (▲).
18. As shown in the figure, Xiao Ming pushed the car parked on the ground with a horizontal thrust of 20 N, but didn't push it. The following statement about this phenomenon is correct (▲)
A, the friction of the car is less than 20n；; B, the car is not subject to static friction.
C, the friction of the car is equal to 20 N d, and the friction of the car is greater than 20 N.
19. Among the following sports, the fastest is (▲).
A, tractor 10 minutes driving 2400 meters, a classmate riding a bike 1 45 seconds driving 1 000 meters.
C, the world record for the 100-meter race is 9.85 seconds d, and the speed in the urban area is 40 kilometers per hour.
20. It is reported that at 3 o'clock in the afternoon of May 1999, a colorful cloud flew over a building under construction with a height of 29 1.6 meters on the site of Shenzhen Seg Square. Suddenly, someone exclaimed that "the building is going to collapse", causing thousands of people nearby to run in panic. The error caused by this judgment is due to the reference object (▲) selected by the observer.
A, building B, ground C, observer himself D, colorful clouds
2 1. In the experiment of demonstrating that sound is caused by object vibration, the tuning fork that is making sound is pressed on the light ball under the suspension line, and the ball bounces off many times. In this experiment, the role of the ball is (▲)
A, amplify the tiny vibration of the tuning fork for easy observation; B, stop the vibration of tuning fork as soon as possible.
C, the vibration time of the tuning fork is prolonged by d, and the sound wave is repeatedly reflected to form an echo.
22. The four pictures below are the imaging situation and correction exercise of myopia (▲).
A.②① B.③① C.②④ D.③④
23. When the light obliquely enters the parallel glass brick from the air, the correct one of the four light path diagrams as shown in the figure is (▲).
24. When the car is parked on the highway, a pair of balance forces are (▲).
A, the gravity of the car and the pressure of the car on the road b, the pressure of the car on the road and the support of the road to the car.
C, the gravity of the car and the attraction of the car to the earth D, the gravity of the car and the supporting force of the road to the car
25. In the experiment of studying convex lens imaging, if the distance from the object to the lens is 15cm and an inverted and enlarged real image is obtained on the light screen, the focal length f of the lens should be (▲).
A, f >15cm b, f < 7.5cm c, 7.5cm.
Second, I will fill in (1 point per grid, ***34 points).
26. The energy stored in food is called ▲ energy. A car driving on a horizontal road has ▲ energy, and a bowstring that is pulled open has ▲ energy.
27. As soon as Xiao Ming and his mother went to the store to buy clothes, he tried on clothes 0.5m in front of the flat mirror, but the image in the mirror left him.
Multiplied by incident angle and refraction angle.
1 10 15. 1
2 20 30.9
3 30 48.6
4 40 74.6
▲ m, when he gradually moves away from the flat mirror, his image height in the mirror will be ▲ (optional: "smaller", "unchanged" or "larger").
28. A classmate studied the refraction law of light and recorded the experimental data as shown in the right table.
⑴ By analyzing the experimental data, it can be known that when light is obliquely incident from one substance to another, the relationship between refraction angle and incident angle is ▲. (2) Please guess that the incident light comes from ▲ when this classmate is doing the experiment. (You can choose "Glass shoots at air" or "Air shoots at glass").
When in distress, passengers are injured when braking.
At 6: 30 this morning, the No.5 bus in this city was in distress and the driver braked urgently. Three passengers sitting in the back row were injured because they suddenly lost their inertia and rushed forward.
29, the ancients said: into the room of Lan Zhi, for a long time without smelling its fragrance; If you enter abalone, you won't smell it for a long time. According to the analysis of scientific knowledge, this is due to brain fatigue.
30. Read the news report in the box. There is a scientific mistake in this. Please find out the mistake in the sentence and correct it. Error: ▲, changed to ▲.
Methyl ethylene propylene
Time14.7s14.2s14.3s
3 1. Three students, A, B and C, took part in the 100 meter race. The recorded time is as follows. The fastest of the three students is.
The reason for the judgment is ▲.
32. The following is a diary written by Jason Chung. Please fill it in:
April 15 Weather: sunny
After dinner today, my mother went to peel yellow peaches for me to eat. Mother peeled it off, pinched it with two fingers and handed it to me. The yellow peach didn't fall because there was a force between her finger and the yellow peach. When I was eating yellow peaches, I dripped the yellow peach juice on the glass counter, forming a small water drop surrounded by ▲ (fill in "thick" or "thin"). Lift the glass table slightly, and through the small water drop, you can see that the words in the newspaper below are vertical and ▲ (fill in "enlargement", "reduction" or "equal size"), and you can see the image of ▲ (fill in "virtual" or "real"). At this time, the small water drop plays the role of a mirror (optionally fill in "concave" or "convex".
33. As shown on the right, the mass of bricks A and B is 2kg. If they are stacked on a level ground, the bricks will
Scientific knowledge of serial number statement
Refracting light from a mirage example
1 ▲
2 immediately ▲
B gravity is ▲ cow, and its force application object is ▲.
34. The language in China is rich and colorful, and many sentences contain scientific knowledge. Please fill in the form with the scientific knowledge involved in the listed sentences.
35. In the experiment of studying convex lens imaging, candles, ▲ and.
▲ Put them on the optical bench in turn. During the experiment: ① A student can only see a broken image at the lower edge of the screen, which is due to the candle flame, the lens and the center of the screen. If you don't change the position of the lens and screen, just move the flame of the candle. If you want to move the image to the center of the screen, you should move the candle flame to ▲. ② Another student keeps the position of the candle and the lens unchanged. No matter how he moves the screen, he can't see the image of the candle on the screen. The possible reason is that. ③ Another student covered the upper part of the convex lens with opaque paper after forming a clear image of the candle flame on the light screen, and asked: At this time, on the light screen (▲)
A. the image disappears completely. B. the upper part of the image disappears. C. the lower part of the image disappears. D. the whole image is still there, but it is a little darker than the original image.
36. When a beam of light hits the mirror at an incident angle of 30 degrees, the included angle between the reflected light and the incident light is ▲ degrees.
37. The vestibule of the inner ear and people who are too sensitive will suffer from dizziness, nausea, vomiting and sweating if they are stimulated for too long or too long. This is commonly known as motion sickness and seasickness. Mobile communication transmits information through ▲.
38. The picture shows an experimental illustration of a classmate exploring the relationship between gravity and mass. The mass of each hook code is 50g.
(1) Complete the following table:
Hook code number (only) Hook code quality (kg) Hook code is affected by gravity (cattle) Hook code to weight ratio (cattle/kg)
1 0.05 0.5 10
2 0.l 1 10
4 0.2 2 ▲
(2) By analyzing the experimental data, we can draw the following conclusions: ▲.
(3) If students hang six hook codes under the spring scale (within the weighing range), the reading of the spring scale is
▲ 。
Third, I can draw (2 points for each small question, 6 points for * * *).
39. Ball A placed on a horizontal table weighs 60 N. Please draw its gravity diagram in figure 1.
40. An object is at rest on an inclined plane, and the pressure on the inclined plane is 30 N. The graphical representation of the force is the pressure, as shown in Figure 2.
4 1. According to the incident light given in Figure 3, please draw the refracted light on Figure 3.
39、 40、 4 1、
Fourth, I will explore (question 43, 3 points, question 44, 2 points, ***5 points)
42. The following is part of the activity process of the scientific experimental team of Class One, Grade Seven, when exploring the influencing factors of sliding friction:
(1) Question: According to the content of study, what do you think they should ask is:
(2) Establish hypothesis: (According to the guesses 1 and 2 put forward by the experimental group, please put forward the third guess)
Guess 1: pressure may be a factor affecting sliding friction;
Conjecture 2: the size of contact area may also be a factor affecting sliding friction;
Guess three:.
(3) Experimental test: Because there are many factors that affect the sliding friction, the control variable method should be adopted in the inquiry process. For example, when testing the conjecture proposed in the above conjecture 2, it is necessary to control the mass of the object to be the same as the roughness of the contact surface of the object, and the amount to be changed is:
43.( 1) The TV remote controller controls the TV by emitting infrared rays, which can be seen by the naked eye.
(2) Three students want to explore the infrared blocking ability of paper, plastic film and cotton cloth. The experimental process is as follows:
The minimum number of layers that a device can completely block a signal.
Xiaoke Paper 14
Xiaoyan plastic film 20
Xiao Jiu Cotton 10
Xiaoke sandwiched a few sheets of paper between the remote control and the TV set at home, and pressed the control key of the remote control with his finger. If the remote control can also control the TV, the amount of paper will increase. Repeat the experiment and gradually increase the number of layers of paper until the remote control can't control the TV. Write down the number of layers of paper.
Xiaoyan, like Xiao Ke, experimented with plastic film in her own home and recorded the number of layers of plastic film. Xiao Jiu, like Xiao Ke, experimented with cotton cloth at home and recorded the number of layers of cotton cloth.
Their experimental results are shown on the right. Therefore, they come to the conclusion that cotton cloth has the strongest ability to block infrared rays.
The main problems in their research process are
Write a specific question, for example, you didn't choose the same TV set (the same remote control) for the experiment. )
V. I can calculate (* * 1 small question, ***5 points)
Car number: Zhejiang JC- 1234
Ride date: April 2006-18
Boarding time: 10:00
/kloc-get off at 0: 05.
One-way fare: 3.00 yuan/km
Mileage: 6.0 kilometers
Amount 16.00 Yuan
44. Once Mr. Zhang worked in Wenling City, and his taxi was driving at a constant speed on a straight highway. The picture on the right shows the fare invoice printed by the computer automatic meter when he arrived at his destination. Q:
(1) Taxi travel time.
(2) the speed of the taxi.
(3) If the starting price of a taxi is 4 yuan, and the unit price is calculated after it exceeds the distance within the starting price, how far can it go at most?
Reference Answers to the Mid-term Examination Questions in Grade Seven Science (Part Two)
I will choose (2 points for each small question, ***50 points)
The title is 1 23455 6789 10.
Answer C A D B C D C C B B
The title is11213141516171819 20.
Answer C D A A C B A C D D
Title 2 1 22 23 24 25
Answer A B A D C
Second, I will fill in (1 point per grid, ***34 points).
26, chemical energy, kinetic energy, potential energy 27, 1, unchanged
28. When the refraction angle is greater than the incident angle (or the refraction angle increases with the incident angle), the glass enters the air.
29, sense of smell 30, due to sudden loss of inertia, due to inertia
3 1, the shorter the time for the same distance, the faster the speed.
32. Friction, thickness, thinness, enlargement, emptiness, protrusion 33, 19.6, Earth
34, light reflection, straight-line propagation of light
35, convex lens, light screen, not at the same height, downward, candle at a focal length, D.
36, 60, 37, semicircular canal, electromagnetic wave, 38, 10, the gravity of an object is directly proportional to its mass, 3 n.
Third, I can draw (2 points for each small question, 6 points for * * *).
Brief answers to drawing questions 39, 40 and 4 1
Fourth, I will explore (question 43, 3 points, question 44, 2 points, ***5 points)
42. What are the factors that affect the sliding friction?
The roughness of contact surface may also be a factor affecting sliding friction.
Size of contact area
43. (1) No.
(2) The positions of shielding materials are different. The distance between the remote control and the TV is different. The thickness of the test material is inconsistent.
V. I can calculate (* * 1 small question, ***5 points)
44.( 1)5 minutes (300 seconds) (1 min)
(2) It is known that s = 6 km = 6,000 m, t=5 minutes =300 seconds.
Then: v = s/t = 6000m/300m = 20m/s (2 minutes)
(3) Let the distance beyond the starting price be s 1.
Then: 3.00 yuan /km× S 1 = 16.00 yuan -4 yuan = 12.00 yuan.
De: s 1 = 4km。
Then: within the starting price, the maximum distance you can walk is 6 km -4 km =2 km (2 points