1. When a glass of water freezes, the ice cubes will break the glass. This is because when water freezes () a, the volume increases by b, the mass increases by c, the volume and mass increase by d, and the volume and mass decrease by 2. Under the following circumstances, the mass of an object has changed as follows: A, a compressed spring B, an object C moving from the moon to the earth, an iron block D heated to red, and a tree has grown tall. Regarding quality, the following statements are correct: () A. After water freezes, the quality becomes larger. B, the iron block is beaten into iron pieces after heating, and the mass becomes smaller. C, the physics textbook is in Nanjing, in Antarctica. B, fitter with file processing; C, rolling the copper rod into a thin copper plate; D: The astronauts brought copper rods to the moon. 5. The objects with the closest mass to 50g may be () A, a grain of sand B, an egg C, a pen D, and the density of a hen 6. Understanding the density formula () A The density of the same substance is directly proportional to its mass and inversely proportional to its volume. B press iron into iron pieces, and the density becomes smaller. Solids and liquids have the same mass and the same volume.

A substance of the same mass has a high density and a large volume. 7. According to the density formula ρ=m/V, the following statements are correct: (a) The density of an object is directly proportional to its mass; B) The density of an object is inversely proportional to its volume; C) The density of an object is directly proportional to its mass and inversely proportional to its volume; D) Density is a characteristic of a substance, which has nothing to do with its mass and volume. 8. The shot put has been used for many years. What hasn't changed is that () A. mass B. volume C. density D. have not changed. 9. A bottle that can only hold 1 kg water can hold 1 kg () A, alcohol B, gasoline C, diesel D and sulfuric acid.

Universe and Micro-world 10, the following statements about molecules are correct: () A, which is the smallest particle in the micro-world; B, the total volume decreases after alcohol and water are mixed, indicating that the molecular volume decreases. C, molecules are the smallest particles to maintain the original properties of substances; None of the above statements is correct.

Chapter 11 of ninth grade physics is less than

The sun will reach the earth in eight minutes. If it takes a year, what do you need?

Notes on Lesson 1 of Chapter 11 of Grade 9 in Physics 1 1 Colorful Material World

1 1. 1 universe and micro-world

Target: 1. You should know that the universe is made of matter, and matter is made of molecules and atoms.

2. Understand the microscopic models of solids, liquids and gases, and understand the structure of atoms.

3. Understand the application and development prospect of nanotechnology and nanomaterials.

Independent research platform

1. the earth and all other celestial bodies are made up of.

2. Most substances become smaller when they change from liquid to solid, mainly because.

3. The following statement is true ()

A. molecules are the smallest particles that make up matter.

B. The nucleus consists of protons and neutrons, which are the finest structures.

C. Liquid substances have no definite shape, but are mobile, and molecules have no fixed position, so they are free to move.

No matter how science and technology develop, people's research on cosmic celestial bodies and microscopic particles is limited.

4. How small is the atom? The best way to answer this question is to compare it with daily necessities. Here are some examples:

The thickness of a piece of paper is equivalent to the thickness of 10000 atoms;

A drop of water contains 20 trillion oxygen atoms and twice as many hydrogen atoms.

News pictures are made up of many tiny inks, and each ink dot contains about 654.38 billion atoms (that is, 654.38+0 followed by 20 zeros).

The atom is so small that no one can really see it for many years.

According to your knowledge, describe what you might see and experience if you were reduced to the size of an atom. Describe other atoms and molecules around you and explore your new world!

Chapter 1 1 of the first volume of ninth grade physics: Wen Ku. Baidu, please. /view/6d 803 dfe 9 10e 12d 2 af 9e 706。

Junior high school physics has chapters. Download it yourself.

9. Physics, Chapter 11, Section 2, Quality Exercises and Answers, Quality of Objects.

Category name

Learning guidance objectives:

Understand the concept of quality, know the unit and conversion of quality;

Understand the structure and use of the balance, and you will use the pallet balance correctly.

Learning guidance process:

Autonomous learning

1, _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

2. unit: international system of units: main unit, commonly used unit: t g mg.

Perceptual understanding of quality: a pin is about 80 _ _ _ _ and an apple is about150 _ _ _.

An elephant is about 6 _ _, and a chicken is about 2 _ _ _.

3. Measure:

(1) Measuring tools commonly used in daily life:,,, Measuring tools commonly used in laboratories _ _ _ _ _.

(2) How to use the pallet balance:

① "Look": those who observe the scales and those who wander on the scales.

② "Release": put the balance on the stage, and put the stray code on _ _ _ _ _ at the end of the balance.

③ "Adjustment": Adjust the position where the indicators at both ends of the balance beam point to the reticle, and then the beam.

④ "Weighing": put the object to be measured into the plate, add and subtract weights on the plate, and adjust the position on the scale until the light beam recovers.

⑤ "Note": the mass of the measured object = the total mass of the weights in the plate+the calibration value of the traveling code on the scale.

⑥ Note: A cannot exceed the weighing of the balance.

Keep the balance dry and clean.

⑶ Method: A. Direct measurement: solid mass.

B. Special measurement: the mass and tiny mass of liquid.

Cooperative investigation

Explore the change of mass when the shape, state and position of an object change.

Conclusion: The quality of an object is an attribute of the object, and it does not change with the change of _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Exquisite instructions

About how to "level" the pallet balance, Xiao Ming made the following summary: the two adjustable parts on the pallet balance are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ When adjusting the beam balance during weighing, if the pointer is found on the right side of the dial, it should be _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Balance is a more precise measuring tool, and the weight can't be used if it is rusty or defective. If the weight rusts (the mass increases), the influence on the measured mass is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Independent evaluation

1, the mass of a piece is about 5×10-4 kg = _ _ _ _ mg, and the mass of a whale is about1.5×105 kg = _ _ _ _ _ t.

2. Fill in the appropriate units of mass of the following objects:

The quality of a bottle of mineral water is 500 _ _ _ _ _ _ _;

The mass of a bicycle is about 20 _ _ _ _ _ _ _;

The mass of a pencil is 2×10-5 _ _ _ _ _ _ _.

3. The quality of "Century Baoding" presented by China to the United Nations is 1.6t, and the quality delivered from China to the United Nations Headquarters is _ _ _ _. Shenzhou spaceship sent a 500-gram national flag into space. In space, the quality of the national flag will be _ _ _ _ _ _ _ _ (fill in "bigger" and "bigger".

4. When the following changes occur, analyze the quality change of the object.

(1) An iron block with a mass of 2kg is heated from 10℃ to 400℃, and the mass of the iron block is _ _ _ _ _ _ _ _ _.

(2) After the ice with a mass of 5kg is melted into water, its mass is _ _ _ _ _ _ _ _ _.

(3) The astronauts took a piece of bread with a mass of 500g into space, and the quality of the bread became _ _ _ _ _ _ _ _ _ _.

5. The mass of an ordinary chicken is about 2.0 _ _ _ _ _ _ _ _; The quality of a middle school student is about 50 _ _ _ _ _ _ _ _; The quality of a stamp is about 0.06 _ _ _ _ _ _.

6, 1kg cotton and 1kg iron, the following statement is correct ().

A. Cotton contains more substances. B. Iron contains more substances.

C. cotton contains as much substance as iron. It is impossible to compare the amount of substances contained in cotton and iron.

7, a glass of water solidified into ice, then the following statement is correct ()

A, its state remains unchanged, and its quality changes; B, its state and quality have changed;

C, its state and quality remain unchanged; D, its state has changed and its quality remains the same.

8, a weighing range of 0 ~ 1000 g balance, which of the following objects can be expressed by it ().

A.a shot put, an apple, a student and a bag of rice.

9. A classmate uses a tray balance to weigh the mass of an object. After adjusting the balance, it was estimated that the mass of the object was about 50g, so he put the object and weight into the plate correctly, and found that the index was obviously biased to the left of the middle line of the plate, which should be ().

A. Reduce weight B. Increase weight

C. move the balance nut at the right end of the beam to the right. Move the balance nut at the right end of the beam to the left.

10. There are scales and walking codes on the cross beam of the pallet scale. The function of the right-shift wandering code is ().

A. it is equivalent to adjusting the balance nut to the left. B. used to indicate balance rather than indicators.

C. It is equivalent to adding a small weight to the left plate D and a small weight to the right plate D..

1 1. When a classmate weighed the mass of an object with a balance, he found that the weight had worn out, so he compared the measured result with the real value ().

A. small b equals c, big d is uncertain

12, a classmate measured the mass of an object with a pallet scale. After the measurement, he found that the object was wrongly placed on the right plate and the weight was placed on the left plate. Because it can't be repeated, he can only set the value according to the measured data. He remembered that 50g and 20g weights were used. As shown in figure 6- 10, the mass of the object is ().

A.68.0g g B.72.0g g C.72.5g g D.67.5g g.

13. Weigh the mass of about 69g items and add the weights to the right plate of the balance in sequence ().

A, 60g, 9g, B, 30g, 30g, 9g

c、50g 10g 5g 2g D、50g 10g 5g 4g

14, (09 Jiangsu) When measuring the mass of copper block with pallet scale, the number of days shall be

Put it flat on the desktop, move the code to the zero scale of the ruler,

If the indicator of the balance is still in the position shown in Figure A, the balance screw can

Adjust the mother's direction (choose "left" or "right") to make the sky even.

Balance. During the measurement, when the weight and deviation code on the right plate are in the position shown in Figure B ..

When the balance is balanced, the mass of the copper block is g.

15, a classmate forgot to adjust the balance of the pallet scale beam. When the indicator is at rest, it points to the right of the center reticle of the dial. Use this pallet scale to weigh the mass of an object. When the day is balanced, the measured mass is the real mass of the object. (Fill in "greater than", "less than" or "equal to")

16. If the balance is equipped with the following weights in the weight box: 200g 1, 100g2, 50g 1, 20g2, 10g 1, 5g 1, 2g2. The maximum weight of the balance is _ _ _ _ _ _____g, and the accuracy it can achieve is _ _ _ _ _ g. When weighing the mass of an object with this balance, there are 1 20g weight, 1 2g weight on the disk on the same day or so. balance

17. In the experiment of measuring the mass of an object with a balance, Xiao Ming first took a tray balance and put it on a horizontal desktop, and found the situation as shown in Figure 6- 1.

(1) The measures he should take are _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;

(2) After the balance is adjusted, Xiao Ming weighs the mass of the object according to the method shown in Figure 6-2. Xiaohua immediately said to Xiaoming, "You made at least two mistakes when operating." Xiaohua said two mistakes are:

①__________________________________________________________,

②__________________________________________________________.

(3) Xiao Ming listened to Xiaohua's advice with an open mind and re-operated. In the process of weighing, the situation as shown in Figure 6- 1 reappears. He should be _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _;

(4) After the balance is re-balanced, the position of the weight and the pendulum code used are shown in Figure 6-3, so Xiaoming's object mass is _ _ _ _ _ _ _ g. 。

18. Measure the quality of nickels with the adjusted pallet balance, and put five nickels in the air.

Put 5g weights on the flat left plate and the flat right plate, and the position of wandering code on the scale is shown on the right. At this time,

The beam of the balance is balanced, and the scale display quality corresponding to the traveling code is _ _ _ _ _ _ _ _ _ g, one fifth.

The quality of the coin is _ _ _ _ _ _ _ _ g.

19, a classmate wants to use scales, weights and glasses.

Water is used to measure the density of salt water. (1) He put the pallet balance on a horizontal table, and the walking code is at the "0" point at the left end of the balance. Before the beam is balanced, the indicator is shown in Figure 2- 1-8 (A), and the operation to be performed at this time is _ _ _ _ _ _ _ _ _ _; After the balance beam is balanced, when weighing the object, he adds and subtracts weights on the right plate of the balance, and the indicator is shown in Figure 2- 1-8 (b). At this time, the operation he should perform is _ _ _ _ _ _ _ _ _ _ _.

20, tray balance on a horizontal desktop, move the adjusting nut to balance the balance, forget to put the stray code on the zero scale of the balance, so the measured mass of the object is compared with the actual mass of the object ().

A. too big B. equals C. too small D. can't judge

2 1. A classmate measured the mass of an object with an adjusted pallet balance.

The operation is as shown on the right, in which the operation error is:

( 1) ;

(2) .

Physical exploration in the first volume of the ninth grade of People's Education Press, Chapter 11 Quality and Answer. Come on! Be sure to understand the definition of quality.

Accompany you to study the ninth grade physics chapter 1 1 answer (section 5 until unit practice), ahem!

Go buy a teacher's book!

There's one in the back!

Ask the exercises in chapter 11 of ninth grade physics, and there is no answer. Just four questions 1. Workers use the pulley block as shown in figure 1 1- 15 to lift heavy objects, regardless of rope weight and friction.

(1) If a worker can lift an object weighing 400N vertically and evenly with a force of 250N, find the mechanical efficiency of the pulley block at this time.

(2) If a pulley block is used to vertically lift an object with a weight of 900N and lift it at a constant speed of 2m, find out the work done by the pulling force F in this process.

2. As shown in figure116, the inclined plane of the experimental device is 2m long and 0.5m high, and the stopwatch scale is1s. The trolley with the weight of 1N is driven along the inclined plane by a pulling force f of 0.3N, and arrives at a constant speed from the bottom.

When it reaches the top, the stopwatch changes as shown in the figure (the indicator does not rotate for more than one revolution). Q:

(1) pull to do work

(2) the power of tension

(3) Mechanical efficiency of inclined plane

3.(05 Lianyungang) As shown in the figure, a wooden board without gravity can rotate around the O point without friction, and a cube P with a length of 50cm is hung at the A end. When a middle school student with a weight of 500N stands at the B point, the pressure of P on the ground is just zero, OA= 1m, OB=3m, so what is the gravity of the object P? When people walk to the left 1m,

4. As shown in Figure 4, a light lever, with a 50N weight hanging on the thin line at the A end, rests on the horizontal ground, and the bottom area of the weight is 40. When a vertical downward force is applied at point B, the wooden pole can be in a balanced state in the horizontal position. At this time, the thin line is vertical, and you will know. Find the pressure of heavy objects on the horizontal ground.

The knowledge points in the first section of Chapter 11 of the ninth grade physics are in the eighth grade.

Vaporization: endothermic

Liquefaction: exothermic

Curing: exothermic

Melting: endothermic

Sublimation: heat absorption

Ninghua: exothermic

Amorphous crystals continue to absorb heat during melting, but the temperature will change. When the crystal melts, the temperature remains unchanged and continues to absorb heat.

Air pressure has an effect on the boiling point of liquid.

Where can someone teach the ninth grade physics chapter 11 examination paper last semester? Thank you. Bookstore.