The water tank thermometer on the dashboard of Chevrolet Sail has no degree display. How do you know that the temperature of the water tank is too high with only a few scales?

A. the front wheel should land first. B. the rear wheel should land first.

C. the front and rear wheels should land at the same time. D. which wheel hits the ground first has nothing to do with the rollover risk.

2. The following statements about laser application are wrong:

A. Indoor laser lighting B. Laser communication

B, processing the hard material d by laser, and performing long-distance ranging by laser.

Seen from the ground, the geosynchronous satellite used for communication is stationary. The time required to run for one week is:

A.24 hours, 23 hours and 56 minutes C. 24 hours and 4 minutes D. 24 hours and 56 minutes

We can distinguish the sounds of piano and violin, because they make sounds:

A. different tones B. different timbre C. different loudness D. different frequencies

A spaceship flew around the earth outside the atmosphere after turning off the engine. Possible phenomena in the spacecraft are:

A. the mass of the object disappears. B. the speed of the object's free fall becomes faster.

C. the candle burns normally. Water droplets float in the air in a spherical shape.

6. Mountain roads often surround the hillside and climb the Panshan Mountain, which can make cars going up the mountain:

A. Improve power B. Improve mechanical efficiency

C. Reduce the required traction

7. During the flood fighting and disaster relief, many people on the levee wore thick vests. The main functions of this "vest" are:

A. it can prevent the transfer of heat, thus resisting the cold.

B. Reduce the force of other objects on human body when falling or colliding, and play a protective role.

C Different vests reflect different colors of light for easy identification.

D. None of the above statements is true.

8. At the station, the passengers sitting in the train found from the window that there were two trains driving in opposite directions. The following judgment was wrong:

A. Between the passenger's train and the two trains he saw, there must be two trains running in opposite directions.

The passenger's train may be moving.

C. three trains may travel in the same direction.

D. one of the three trains may be stationary.

9. After turning off the engine, the space shuttle is flying in space. If scientists want to do experiments in it, which of the following operations can't be carried out normally:

A. measure the temperature with a thermometer. Measure the force with a spring scale

C. measure the mass with a balance. Measure time with an electronic watch.

10. There are two eggs, which are cooked once in a lifetime. Let them start to rotate at the same speed on a smooth horizontal desktop:

A. Raw eggs stop spinning soon, and cooked eggs stop spinning for a period of time.

B. The boiled eggs stop spinning soon, and the raw eggs stop spinning for a while.

C. the two eggs quickly stopped turning.

D. Two eggs turn for a while, and then stop at the same time.

1 1. There is a plane moving horizontally to the left in a straight line at a constant speed, every 1 second.

A small ball was gently placed on the plane. When three balls fell, none of them fell to the ground.

If air resistance is not considered, which of the following pictures should be the arrangement of these three balls in the air:

Two. Fill in the blanks (***28 points, 2 points for each blank)

1. It is known that the density of air is 1.29 kg/m3, and the average density of human body is equivalent to that of water. The buoyancy of a person with a mass of 60 kilograms in the air is about _ _ _ _ _ _ _ _ cattle.

There is a big wooden pole on the ground. It takes 300 Newton to lift the A end and 200 Newton to lift the B end. The _ _ _ _ _ _ _ end of this wooden pole is relatively thick, and the weight (gravity) of the whole wooden pole is _ _ _ _ _ _ _.

As the picture shows, four identical glass bottles are filled with water, and the water levels are different. Blow near the bottle mouth. If you can play the four scales of Dou (1), Ruai (2), Mi (3) and Fa (4) respectively, then the bottle numbers corresponding to these four scales are _ _ _ _ _ _ _ _ _.

Xiao Ming came home from school when it was windy and rainy. He was running from west to east at the speed of 18km/h when he found a strange phenomenon. Raindrops fall vertically. Please confirm that it was _ _ _ _ _ _ wind, and the wind speed was _ _ _ _ m/s.

5. When the rear-wheel drive vehicle accelerates forward on a flat road, the direction of friction between the ground and the rear wheel is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

6. There is a concert in the concert hall, the baritone is singing loudly, the soprano is singing softly, and there are many instruments to accompany it. At this time, the baritone's _ _ _ _ _ _ _ is bigger than the soprano, and the soprano's _ _ _ _ _ _ _ is higher than the baritone. The sound of the concert sounds three-dimensional, which is mainly due to the _ _ _ _ _ _ effect of human hearing.

Iii. Answer the following questions briefly (*** 14)

1、

2.(4 points) During the festival, the hydrogen balloon floated into the sky, getting smaller and smaller, and gradually disappearing. Imagine what the balloon will eventually look like. Make a prediction based on what you have learned in physics and explain the reasons.

3.(6 points) If you want to learn physics well, you should do more experiments. Please list three kinds of physical experimental instruments made of large plastic coke bottles, and briefly describe the manufacturing process and the physical phenomena demonstrated.

(10) Xiaoying designed an experiment to verify the relationship between the internal pressure of water and the water depth. The equipment used is shown in the figure. Increasing the sand in the tubule can change the depth of the tubule sinking into the water.

1. Indicate the required measuring tools and indicate the physical quantity to be measured with letters.

2. Write out the experimental steps one by one.

3. According to the measured data, the pressure calculation formulas at different depths are derived.

4. The experimental results show how to judge whether the internal pressure of water is proportional to the water depth.

5.( 10 minute) There is a milestone every 1 km by the roadside, and the distance from the starting point of the highway to this monument is indicated in kilometers. In this paper, a method of measuring the speed of bicycles at medium and uniform speed by using milestones and watches is designed, and the calculation formula is given. The calculation results are in kilometers per hour. In order to reduce the error in measurement, please put forward at least two points for attention.

6.(6 points) In the interesting physical performance, Xiao Ming showed the water storage and drainage device as shown in the figure. If the original water tank is empty, when the water level in the water tank is higher than what point, will water flow out of the drain? If the original water tank is full, when the water level in the water tank drops to what point, will the drain pipe stop draining? If the water inlet keeps filling the water tank, but the water inlet is so small that when water flows out of the water outlet, the water inlet is less than the water outlet. What are the characteristics of the water flow at the outlet?

7.( 10) The mass of pressure limiting valve of 24cm pressure cooker is 0. 1kg, and the inner diameter of exhaust hole is 3 mm.. If it is used to boil water for disinfection, what is the highest temperature of this pressure cooker according to the relationship between boiling point and pressure of water in the table below?

T/℃

90

95

100

105

1 10

1 12

1 14

1 16

1 18

120

122

124

126

128

130

Pressure/kPa

70

84

10 1

12 1

143

154

163

175

187

199

2 1 1

226

239

258

270

Eight. (10) Figure 10 shows the automatic drinking water device for livestock in design. The bottom cover A usually supports the water outlet of the water tank. Once the water level in the drinking water tank drops, the buoyancy of the float decreases, and water flows into the drinking water tank from the small water tank. In the design, the highest water level of the water tank is 60 cm, the diameter of the water tank outlet is 6 cm, the total mass of the bottom cover A and the vertical bar B is 420 g, the mass of the float D is 580 g, and the volume is 2 decimeters 3, and the mass of the cross bar C can be ignored. The calculation shows that this automatic device can't work normally when the water tank is full of water.

Physics Application Test 2 Answer (Mechanical Part)

1. 1, B 2, A 3, B 4, B 5, D 6, C 7, D 8, A 9, C 10, a1,c.

2. 1, 0.76 2, a, 500 3, c, b, a, D 4, w, 5 5, horizontally forward, horizontally backward.

6, loudness (or volume, sound), tone (or frequency), ears

Three.

2. There are two possibilities. First, due to the gradual thinning of the high-altitude gas and the decrease of pressure, the internal pressure in the balloon is greater than the external pressure during the rising process, and the balloon keeps expanding and eventually "explodes" and ruptures.

On the other hand, due to the thin air at high altitude, the buoyancy of the balloon gradually decreases. When buoyancy equals gravity, the balloon rises at the maximum speed. Then, the buoyancy is less than gravity, and the balloon begins to decelerate upward. After the balloon speed is zero, it accelerates to fall and its buoyancy gradually increases. When it passes the position where buoyancy is equal to gravity, the balloon begins to decelerate downward. After the speed of the balloon dropped to zero, it began to accelerate again.

3.① Make a measuring cup, quantitatively pour water into the bottle with the existing measuring cylinder in the laboratory, and mark it.

(2) As a liquid side pressure tester, small holes with the same size are punched at different heights of the measuring wall of the bottle. After pouring water, the pressure inside the liquid can be directly reflected from the water flow.

(3) Demonstrate that the sprayer is inserted into the capped coke bottle with a thin plastic pipe, and the coke bottle is squeezed hard by hand, so that the water is sprayed out of the thin plastic pipe in mist.

Four. 1. The measuring tool needed is a ruler; It is necessary to measure the diameter d of the tubule and the depth H 1, H2 of the tubule submerged in water.

2. Experimental steps: ① Measure the diameter d of tubule; (2) adding a small amount of sand into the thin tube, putting the thin tube into a container filled with water, and measuring the depth of the thin tube sinking into the water with a ruler after balancing; (3) Increase the sand grains in the thin tube, then put the thin tube into a container filled with water, and measure the depth H2 of the thin tube sinking into the water with a ruler after balancing.

3. Derive the formula for calculating pressure. In equilibrium, the gravity G tube on the thin tube (containing sand) is equal to the buoyancy F floating, that is,

G tube = f float,

G tube = P 1s = F float = water g, so p 1= water g.

4. It can also be proved that p2= water g, so the internal pressure of water is directly proportional to the water depth.

Answer: In the process of riding, choose a relatively flat road, and first write down the time t 1 and the landmark number L 1 that passed a certain milestone. After driving at a constant speed for several kilometers, write down the time t2 and milestone number L2(t 1 and t2 are in seconds) after passing another milestone, and the cycle speed is: V = 36000.

In order to reduce the error, it is necessary to (1) record t 1 and L 1 only after the vehicle speed is stable.

(2) Use an analog watch with a second hand or a digital watch that can read seconds.

(3) The driving distance should be several kilometers, neither too short nor too long.

6. Reference solution: During water injection, when the water level is higher than point D, the water will flow out, and when the water level drops to point C, the water will stop ... and the drain pipe will drain intermittently. Scoring standard: * * 5 points for this question. 2 points for the first question, 2 points for the second question and 1 point for the third question.

VII. Reference solutions:

( 1) (2)

(3)

Substitute (1) and (2) into (3) and (4).

Substitution value

P = 2.4× 105 Pa (5) As can be seen from the table, the temperature in the pot is about 126℃.

Scoring standard: 6 points for this question, (1), (2), (3), (4) and (5) each 1 min, and the temperature in the pot 1 min (the temperature is126℃ ~1min.

8. Reference solution: As shown in Figure 13, the forces acting on the bottom cover, upright post and float are: upward buoyancy:

F float = ρ VG =103× 2×10-3× 9.8 =19.6 (cattle)

Total downward gravity: gTotal =(0.42+0.58)×9.8=9.8 (Niu)

The downward pressure of water in the water tank: F pressure = ρ GHS =103× 9.8× 0.6× 3.14× 0.032 =16.6 (cattle).

∫ sum of downward force f downward = gTotal+fPressure = 26.4 n > fFloating ∴ The bottom cover A will move down and the device will not work normally.