Physical problems. . . . Number eight. . . . . . O(∩_∩)O Thank you ~ ~ ~ ~

It's PEP's, right?

1. Fill in the blanks (65438+ 0.5 points for each small question, ***45 points)

1, a classmate measured some data, but forgot to write the unit. Please give him a suitable unit:

A. Xiaohong's height is1.65 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

C, the half-court football match is 45 _ _ _ _ _ _ min, D, the height of a classroom is about 3 _ _ _ _ _ _.

2, the speed of light in a vacuum is _ _ _ _ _, the sun can reach the earth in about 8_, and the distance from the sun to the earth is about _ _ _ _ _, the speed of light in other transparent substances is slower than that in a vacuum _ _ _ _.

3. The sound is produced by the vibration of the object _ _ _ _ _, and the flute sound is produced by the vibration of the air column in the pipe _ _ _ _. Astronauts on the moon talk by radio because _ _ _ _ can't spread sound.

4. Someone sits on the boat at a constant speed. Compared with people, the boat is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. If the ship's speed is 2m/s, then after10s, the ship has passed _ _ _ _ meters.

5. A classmate has measured that her average walking speed is 1.2m/s_, that is _ _ _ km/h, and her home is 720m away from school. In order not to be late, she should leave home at least _ _ _ _ _ _ minutes in advance.

6, A, B two objects moving in a straight line at a uniform speed, the ratio of the distance passed is 3: 2, and the ratio of the time spent is 2: 3, so the ratio of their speeds is _ _ _ _ _ _.

7.a and B are 32m apart. When an object moves from A to B at variable speed, it takes 4s to move from A to C on the way. After staying here for 1s, it takes 3s to move on to B, so the average speed of an object from A to B is _ _.

On a quiet night, the moon appeared in the well. The naughty little monkey hung upside down on a rope and tried to salvage the moon. Anyway, they can't catch it. When the little monkey was in a hurry, a little monkey fell into the well. Oh, no! The moon is gone. The moon in the well is imaged by _ _ _ _ _, and the disappearance of the moon is the reason why the calm water surface is broken and _ _ _ _ _.

9. Sunlight is composed of red, orange, … _ _ _ _, and the picture of color TV is composed of _ _ _ _ _ _ _.

10, the lens of the eye is equivalent to a _ _ _ _ _ lens. The light of the object passes through the pupil and is imaged on the retina through the lens. If the lens is diseased, people will not be able to see things clearly. If it is imaged in front of the retina, it will be corrected with a _ _ _ _ lens.

1 1. When observing an object with a magnifying glass, the object should be placed within _ _ of the convex lens.

12, the force produced by object deformation is called _ _ _ _ _ _. The attraction among friction, gravity, tension, pressure and charge in life belongs to _ _ _ _.

13, and the picture on the right shows the situation of "tortoise and rabbit race". After the start of the race, "spectators" thought that the rabbit running in front was faster than _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. Because the rabbit was paralyzed and underestimated his enemy, he slept in the middle. By comparison, the "referee" decided that the tortoise who reached the finish line first was fast. In physics, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ refers to

14, people put on roller skates and pushed the wall hard. People are _ _ _ _ _ _ _ objects, and the walls are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Second, multiple-choice questions (3 points per grid, ***30 points)

1, "If I see farther than others, it is because I stand on the shoulders of giants." Who said this famous saying ()

A, Einstein B, Newton C, Deng Xiaoping D, Mao Zedong

2, the length of your body close to 50 mm is ()

A, thumb nail width b, thumb length c, shoulder width d, hair diameter.

3. There is a sign on the bridge as shown in Figure 3, which means ().

A, cars passing through 150N cannot pass.

B 147 is allowed for heavy trucks.

C. The bridge quality is 15t.

D, bridge length 15m.

4, the following measures to reduce noise, belong to weaken in the process of communication is ()

A, the noise of the construction site should be limited. B. plant grass and trees in the urban area.

C. wear anti-noise earplugs; D, urban car horn is forbidden to ring.

5. A classmate stood in front of a flat mirror and looked in the mirror. Her appearance in the flat mirror is ().

One, a real image bigger than her, and a real image smaller than her.

C. Virtual image D is smaller than her, and the virtual image is as big as her.

6. Regarding the phenomenon of light reflection, the following statement is correct.

Light from air perpendicular to the water surface cannot be reflected.

B. An incident ray has multiple reflected rays on an interface.

C, when reflection occurs, the optical path is reversible.

D, when the incident light is close to the normal, the reflected light is far away from the normal.

7, the following instruments become magnified real image is

A, magnifying glass _ _ b, camera _ _ c, flat mirror _ _ d, slide projector

8. The original length of the spring is10cm. When a weight of 100N is hung, the spring becomes 12cm. If a 200-Newton weight is suspended, the length of the spring becomes _

a、 16cm____B、6cm _ _ _ _ C、 14cm _ _ _ _ D、 19cm

9. In order to reduce friction, the following examples are

A, improve the speed of the object _ _ b, hard on the brakes when emergency braking.

C, put a small wheel on the suitcase, and _ _ _ _ _ _ D apply magnesium powder to the weightlifter before lifting the barbell.

10, if the air resistance is not released, all the stones thrown from the hand are in the air.

A, gravity and hand thrust _ _ b, gravity

C, gravity and the earth's gravity _ _ D, forward momentum

Iii. Drawing (9 points)

1, complete the light path diagram shown below, and draw the appropriate type of lens in the box.

As shown in the figure below, the sunlight forms an angle of 60 degrees with the horizontal plane. Use a plane mirror to make sunlight shine vertically on the bottom of the well. Please draw a picture to determine the position of the plane mirror and mark the degree of the included angle between the plane mirror and the horizontal plane.

3. As shown in the picture on the right, put an object weighing 40N on a horizontal table, and draw a force diagram to draw the force on the object.

Four, experimental questions (9 points)

1, (3 points) A classmate made a flat mirror imaging experiment with candles, glass plates, scales and other equipment, and obtained the following data.

Distance from candle to flat mirror

5cm 5cm

10cm 10cm

15cm 15cm

From these data, you can draw the conclusion that _ _ _ _ _ _ _ _ _ _ refers to

2. Please fill in the missing contents in the inquiry report below.

⑴ Ask a question: Does the average speed change when the car is driving along the slope from top to bottom?

(2) Guess (please guess the question): (1')

(3) Experimental design scheme:

Experimental equipment (as shown in figure 1 1): long board, wood block, trolley, scale, stopwatch.

Figure 1 1

Main experimental steps: (2')

Experimental data record table (designed experimental data record table): (2')

⑷ Experimental conclusion: 1'

Five, the calculation problem (7 points)

Taxi fare invoice

Car number

Chuan F-7 1238

Date 05-09-28

Get on the bus 10: 00

/kloc-get off at 0: 05.

The unit price is 2.00 yuan.

The mileage is 6.0 kilometers.

The amount is 16.00 yuan.

Someone took a taxi and drove at a constant speed on a straight highway. On the right is the fare invoice when he arrived at his destination by bus. Q:

(1) Taxi travel time.

(2) the speed of the taxi.

Sorry, there are no answers to these questions.

1. Fill in the blanks (65438+ 0 for each blank, ***28)

1. The speed of light propagation in vacuum is _ _ _ _ _ _ _ km/s. In the Milky Way, the closest star to the sun is Alpha Centauri (also known as "proxima centauri"). It takes 42 years for the light from Alpha Centauri to reach the Earth, so the distance from Alpha Centauri to the Earth is _ _ _ _ _ _ _.

2. Two cars are driving in tandem at the same speed on a straight road. If the car behind is taken as a reference, the passengers in the car in front are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

3. Fill in the appropriate units for the following figures: the speed of the train is generally120 _ _ _ _ _ _ _ _ _; The quality of a piece is about 500 _ _ _ _ _ _.

When an object moves in a straight line, the distance it passes in the first 2s is 40m, and the distance it passes in the second 2s is 20m. The average speed of this object in the second second is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

5. Unit conversion: 72km/h = _ _ _ _ _ m/S2.7x103kg/m3 = _ _ _ _ _ _ g/cm3.

6. Take an object with a mass of 2kg from the moon and bring it back to Earth. The mass of this object is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (g = 9.8n/kg).

7, a stone tablet, 50 cm long, 20 cm wide, 3 meters high and 0.75 tons in mass, then its density is _ _ _ _ kg/m3; 1/4 is removed from it, and the density of the remaining part is _ _ _ _ kg/m3.

8. The total mass of a glass bottle that can hold 500 grams of water is 750 grams. When a bottle can hold _ _ _ _ _ ml of alcohol with a density of 0.8 g/cm3, the total mass after being filled with alcohol is _ _ _ _ _ g. ..

9. A beam of light shoots into the air from a transparent material. The included angle between the incident light and the interface is 60, the included angle between the refracted light and the incident light is150, and the reflection angle is _ _ _ _ _ _ _ _ _ _.

10, the athlete lifts the barbell, and the athlete has an upward lifting force on the barbell. The object of this force is _ _ _ _ _ _ _ _ _.

1 1, gravity is _ _ _ _ _ _ _ _ _ _, and the direction of gravity is always _ _ _ _ _ _ _ _.

12, the ball bearing is an indispensable part of the machine, which can change _ _ _ _ _ _ _ _ friction into _ _ _ _ _ _ _ _.

13. Two horses pull the cart horizontally together. One horse is 280N and the other is 260N, so the resultant force of the cart is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

14. As shown in the figure, a 30N wooden block A is pressed against the wall and stands still. If the pressure f is 8N, then the friction force A receives from the wall is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Second, multiple-choice questions (2 points for each question, * * 30 points, single choice)

1, the following statement is true ()

A only static objects on the ground can be selected as reference objects.

B, can choose any object as a reference, but in the specific choice, according to the actual situation.

C only objects on the earth can be selected as reference objects.

D, study the movement of objects, and choose the sun as a reference, because the sun is a truly motionless object.

2. The speed is 10m/s, which is pronounced as ().

A, per second10m b, per second10m c, per second10m d, per second10m.

3. Party A and Party B run 100 meters. When Party A reaches the finish line, Party B is still 10 meters away from the finish line. Now let Party A's starting line fall back 10 meter, and everyone will race at the original speed, so the first one to reach the finish line is ().

A, A arrives at B first, B arrives at C first, and D arrives at the same time. There is no comparability.

4, a glass of water into ice, then its ()

A, the volume becomes smaller and the quality remains the same; B, the volume becomes smaller and the mass becomes smaller.

C, the volume becomes larger, the mass remains the same D, the volume remains the same, and the mass becomes smaller.

5. Use the tray balance to measure the quality of the tack. The following simple and correct method is ().

A, put a tack in the balance plate, measure repeatedly, and take the average.

B, put a thumbtack in the balance plate and measure it carefully.

C, put a thumbtack into a beaker, measure its total mass with a ceiling plate, and then subtract the mass of the beaker.

D, put one hundred tacks in the balance plate, measure its total mass, and then calculate.

6. Four cubes A, B, C and D made of the same substance. Their side lengths are 1 cm, 2 cm, 3 cm and 4 cm respectively. The mass is 3g, 24g, 64g, 192g. Then one of them must be hollow, and it is ()

A、A B、B C、C D、D

7. If the density ratio of three objects (A, B and C) with equal mass is 3:2: 1, the volume ratio of the three objects is ().

a、3:2: 1 B、 1:2:3 C、2:3:6 D、6:3:2

8, "flowers in the mirror, the moon in the water" phenomenon ()

A, light travels too fast. B, light reflection.

C, light is refracted d, and light travels in a straight line in the same substance.

9, as shown in the figure, convex lens, if it is a projector for writing, the object should be placed in the position of ().

A, point a, point b, point B.

C point c point d point e point

10, g=9.8N/kg, that is to say ().

A, 1kg is 9.8N B, the gravity of the object is 9.8 times its mass c, and the mass of the object is1kg; The gravity of an object weighing 9.8kg is 9.8 D, and the gravity of the object is1n.

1 1, assuming that the friction between all objects suddenly disappears, which of the following phenomena is impossible ()

A, we won't be able to walk, and our feet will slide between the ground. B, we won't be able to write because the pen will fall out of our hands.

Conveyor belts will be able to transport goods faster. D, the breeze along the track direction can blow the train.

12, in the following cases, the object motion state changes is ().

A, the object is always at rest; b, the saw blade is flattened; c, the car starts from the rest state, and the plane flies in a straight line at a constant speed.

13. When the pin is attracted by the magnet, the big head is aimed at the magnet ().

A, there is no force, because the pin is only attracted by the magnet, not the pin attracts the magnet.

B, there is no force, because the pin is not a magnet and cannot attract other objects.

C, there is no force, because the needle is very thin

D, strong action, because the forces between objects are mutual, magnets attract pins, and pins attract magnets.

14, the shell keeps moving because ()

A, the driving force of gunpowder B, the thrust of the shell is greater than the resistance of the air.

C, the shell has inertia d, and the inertia of the shell is greater than the air resistance.

15. A weight of 5× 104N is hung under the crane arm. In the following cases, the tension t of the wire rope on the weight is ().

A, when the weight is at rest, T= 0N B, and when the weight rises at a constant speed, t > 5× 104n.

C, when the weight falls at a uniform speed, t < 5× 104 N d, and in the above three cases, t is equal to 5× 104 N.

Three, painting questions (8 points)

1. Draw a gravity map on an object A with a weight of 30 N as shown in Figure A below.

2. As shown in Figure B below, object B moves in a straight line at a uniform speed on a smooth horizontal plane and is subjected to _ _ _ _ _ _ forces. The schematic diagram of the forces shows these forces.

3. as shown in fig. c, it is known that S' is the virtual image of the luminous point s in the plane mirror. Try to draw the position of the plane mirror in the picture.

Methyl ethylene propylene

Four, experimental questions (65438+ 0 points per grid, ***20 points)

1. The existing equipment in the experiment of "measuring the average speed" is a car, an inclined plane and a piece of metal, but the missing equipment is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Fill in the form below according to the pictures below.

Time to pass AB section Average speed of AB section (m/s) Average speed of BC section (m/s) Average speed of AC section (m/s) Average speed of AC section.

2. When using the pallet balance to measure the mass:

(1) Put the balance on the horizontal workbench, put _ _ _ _ _ on the zero scale line at the left end of the scale, and adjust _ _ _ _ _ at the right end of the beam. When the pointer is aimed at the center red line of the dial, the light beam will be balanced.

(2) The mass of the measured object shall not exceed _ _ _ _ of the balance.

(3) Use _ _ _ _ _ when picking heavy objects, and don't hold them by hand.

3. The laboratory has the following equipment: balance, weight, aluminum block, salt water, measuring cylinder, balance, water, beaker and triangle.

(1) If you want to measure the density of brine, you need to choose the following equipment: balance, weight, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

(2) The experimental steps are as follows: a. Put the balance on a horizontal platform and balance it; B. measure the volume of brine with a measuring cylinder (V 1); C, weighing the mass of an empty beaker with a balance M 1; D, measuring the volume v2 of the aluminum block with a measuring cylinder; E, measuring the total mass m2 of the brine and the beaker with a balance; F, measuring the mass m3 of the aluminum block with a balance; G. measure the volume V3 of water with a graduated cylinder.

The reasonable and necessary step for measuring the density of brine is _ _ _ _ _ _ _ _ _ _ _ _ (fill in the serial number).

(3) According to the steps, write the formula ρ = _ _ _ _ _ _ _ _.

4. Spring dynamometer is a commonly used force measuring tool in laboratory. Before measuring with a spring dynamometer, if the pointer of the spring dynamometer is not aligned with the zero scale line, you should measure _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. As shown on the right, it is a white paper for studying the calibration of spring dynamometer. The "0" line is the position of the pointer when no force is applied. At the position indicated by the pointer in the figure, the applied force is 1.5 N, so the force represented by each grid on the paper strip is _ _ _ _ n. ..

Five, the calculation problem (***8 points)

1. It is necessary to measure the density of irregular wood blocks. First, use a balance to weigh the mass of the wood block as 15g, take a measuring cylinder, and put the iron block into the water of the measuring cylinder until the water level rises to the 80mL scale line. Take out the iron blocks and tie them together, then put them into the measuring cylinder, and the water level rises to the 105mL scale line. What is the density of this block? (4 points)

2. Two bicycles, A and B, are driving in the same direction at the same speed on a straight road. A car travels in 5 minutes 1800m, and B car travels 9km in 0.5h h. Car B passed the road sign A two minutes earlier than car A. How far was it from the road sign when car A caught up with car B? (5 points)

Six, the application problem (5 points)

1, a classmate put two nails on the left plate of a leveled balance, and then put five buttons or four nuts on the right plate when the balance was balanced; He put four buttons on the left plate, three nuts and a weight of 1g on the right plate, and the balance was also balanced. The mass of each nail is _ _ _ _ _ _ _ _ g, the mass of each button is _ _ _ _ _ _ _ g, and the mass of each nut is _ _ _ _ _ _ _ _ _ g.

2. As shown in the figure, A and B are the same trapezoidal object, and they all move in a straight line at a constant speed on the same horizontal plane in each figure, so the correct magnitude of the pulling force is ().

a、F2> F 1> F4> F3 B、F2> F 1= F4> F3 C、F2> F4> F 1> F3 D、F2> F3> F4> F 1

The answer to the physics examination paper of the second day of junior high school

First, fill in the blanks:

1, 3.0× 105 2, stationary motion 3, km/h mg 4,10m/s15m/s.

5, 20 2.7 6, 2 kg 19.6 Newton 7, 2.5× 103 8, 500 650

9.30 60 10, barbell athlete 1 1. Due to the gravity of the earth, the force on the object is vertical downward.

12, sliding roll13,540 horizontally eastward14,30 vertically upward.

Second, 1, B 2, B 3, A 4, C 5, D 6, c

7、C 8、B

9、C 10、C 1 1、C 12、C 13、D 14、C 15、D

Third, drawing questions

1, 2, 2 force 3,

Fourth,

Time to pass AB section Average speed of AB section (m/s) Average speed of BC section (m/s) Average speed of AC section (m/s) Average speed of AC section.

2 0.5 1 1 3 0.67

Answer: 1, graduated stopwatch

2.( 1) Balance nut (2) Measuring range (3) Tweezers

3.( 1) Saline measuring cylinder beaker (2)a, C, E and b (3)

4. The straight line is 0.5.

Verb (abbreviation of verb) 1. Known: m= 15g, v = v3-v2 =105ml-80ml = 25ml = 25cm3.

Seek: ρ

Solution:

2. it is known that tA=5min=300S, SA= 1800m, tB=0.5h, SB=9km △t=2min= 120S.

Q: When A caught up with B, it was far from the road sign S.

Solution:

When crossing the road sign, A is in front of A: △S=vB△t=5m/s× 120s=600m.