• Physics is important in school course, it gives an idea about the world around us and its phenomena, about technology and electronics that play important role V modern world. However, not all schoolchildren find the subject equally easy, especially since its important aspect is the ability to solve problems. To interest children and teach them how to correctly apply formulas, we have developed GDZ in physics for grade 9 - a collection of problems by authors V.I. Lukashik and E.V. Ivanova. The manual will help you master solving tasks of varying complexity.
• Using a solver, students do not have to worry about using theoretical knowledge incorrectly somewhere or getting confused with the solution steps. practical problems. The manual is compiled according to the structure of the problem book itself and includes the same sections. It provides an algorithm for applying formulas and physical laws in practice, so it will not be difficult for the guys to understand it.
• Ninth-graders will study solving problems involving evaporation and boiling, become familiar with heat engines, and learn to use the formulas for current, voltage, and resistance. GDZ using the problem book will familiarize students in more detail with calculations of problems according to Ohm’s law, exercises on the propagation of light, its refraction, display, and other types of tasks. This manual is an excellent opportunity to prepare well for the final tests.

Collection of tasks for successful preparation for the OGE

• For effective preparation ninth-graders require a special plan for the final test in physics and high-quality educational materials and workbooks for them, as well as patience and responsibility in order to fully master the difficult course of the discipline. A number of physics and mathematics lyceums, despite the fact that physics is an elective discipline for the OGE, recommend that their ninth-graders take it in the exam without fail. Preparation requires increased attention and scrupulous study of the material.
• Application GDZ greatly increases the chances of success. This is due to such components as:
  - the ability to study at your own pace, based on your capabilities and abilities. Having developed a personal plan and schedule of classes, you can independently monitor the results and adjust the progress of the preparatory work;
  - in ready-made homework assignments, the technology for recording the correct answer is clearly displayed. What is especially important when recording results in physics. Often a correctly solved problem is recorded incorrectly, which leads to an offensive underestimation of points;
  - according to collections GDZ you can trace the logic of obtaining the correct solution. For example, a series physical problems solve correctly not by substituting parameter values, but by a system - this reduces the time for solving and allows you to avoid erroneous conclusions. If a ninth-grader constantly sees the correct course of a solution, he will automatically solve problems correctly and competently.
• Among the effective, interesting and useful workshops that experts recommend supplementing basic textbooks is a collection of problems in physics for the 9th grade, compiled by V. I. Lukashik. Multiple reprints of this book are clear evidence that it contains effective ones that do not lose their relevance exercises to develop skills in correctly solving problems in physics. Many subject teachers recommend this problem book for preparing for subject Olympiads and competitions held at school and extracurricular sites. It is also useful for eleventh-graders who have chosen physics to take the Unified State Exam. You can include a problem book in your teaching materials, even if the basic textbook was written by another author. The versatility and diversity of tasks will make training especially effective and efficient.

Physics solution book for grade 9 Peryshkin is a collection of ready-made homework assignments, including answers to practical questions and problem solving, of a classic physics textbook used in all secondary schools Russia - a manual compiled by A.V. Peryshkin. and Gutnik E.M.

Physics solution book for grade 9 Peryshkin - answers to questions

In the 9th grade, schoolchildren think not only about the current completion of homework, but also about successfully passing the final exams due to their receipt of incomplete secondary education.

GDZ in physics for grade 9 Peryshkin, which contain not only ready-made answers, but also a step-by-step algorithm for solving problems and explanations of theoretical questions, can be a significant help in this matter. If a student does not understand the mechanism for solving a problem, he can turn to a solver and figure out how to do it homework on one's own.

Our website provides schoolchildren with a convenient algorithm for using ready-made homework assignments:

• You can access the site not only from a computer, but also from a phone or tablet;
• in the search bar you need to enter the name of a physics textbook;
• In the table that appears, select the task number and instantly receive an online answer.

This procedure for working with the site is not only convenient, but also significantly saves the student’s time, which is already short due to the high academic load.

Since we regularly update the database of solution books, here you can find the most current editions.

GDZ in physics for grade 9: Peryshkin, Gutnik - white textbook 2014-2017.

Russian ninth-graders learn the basics of physics based on the textbook by Peryshkin A.V. and Gutnik E.M., which was released in 2014 by the Drofa publishing house.

Structurally tutorial consists of 5 chapters, at the end of each of which there is a set of tasks and questions aimed at consolidating the acquired theoretical knowledge. Topics studied in the 9th grade physics course include:

• Patterns of interaction and movement of bodies;
• Propagation of sound, vibrations and waves;
• The structure of the atomic nucleus and features of the use of nuclear energy;
• Electromagnetic fields, their characteristics and properties;
• The evolution of the Universe and its modern structure.

The manual contains 9 laboratory work, which are aimed at practical consolidation of acquired knowledge through experiments and experiments conducted in the classroom.

In task No. 9 of the Unified State Exam in physics, it is necessary to demonstrate knowledge in the field of such a branch of physics as thermodynamics. The work of an ideal gas, the efficiency of heat engines, cycles - this is what awaits us in the ninth task.

Theory for task No. 9 of the Unified State Exam in Physics

Ideal gas work

Let the gas be in a vessel that has a piston. Work is equal to the product of force and displacement: A=F(h 1 – h 2).

The pressure force on the walls of the vessel and the piston is equal to the product of the gas pressure p and the surface area S. Then the work done by the gas is

A=pS(h 1 – h 2) = p(Sh 1 – S h 2) =p(V 1 –V 2)

Therefore, a gas does work if its volume changes.

At constant pressure, work is the product of pressure and volume difference.

Gas molecules have kinetic energy and, when the gas is strongly compressed, behave like elastic bodies. This means that they also have potential energy. Kinetic and potential energy The molecules that make up the gas add up to the internal energy of the gas U.

The internal energy of a gas can be calculated using the formula:

where ν is the amount of substance, measured in moles; R – universal gas constant (R=8.31 ​​J/(mol K)); T – gas temperature.

If you simultaneously change the temperature T and pressure p with volume V, it is difficult to understand the patterns of changes in the state of the gas.

Gas processes

1. Isobaric the process occurs at constant pressure, i.e. p = const. With it, heat Q is expended to increase the volume of gas and increase the temperature.
2. Isochoric the process occurs while maintaining a constant volume, i.e. at V = const. In this case, no work is performed, and the heat received by the gas is spent on changing the internal energy.
3. Isothermal takes place at a constant temperature (T=const). In this case, heat is used to change volume, that is, to perform work. In an isothermal process, Q = A.

Graphs of gas processes are shown in the figures below.

The amount of heat that must be expended when heating a body mass T, on Δt degrees, determined by the formula Q=cmΔt. Here c is the specific heat capacity of the material from which the body is made.

Heat engine efficiency

Here Q 1– the amount of heat received from the heater, Q 2- the amount of heat that is given to the refrigerator, A- useful work.

Analysis of typical tasks No. 9 of the Unified State Exam in Physics

Demo version 2018

Solution algorithm:

1. Let's analyze the problem condition. We write the equation of the 1st law of thermodynamics.
2. We write down the formula for calculating internal energy. We find its value.
3. We define the work

Solution:

1. According to the conditions of the problem, the gas received 50 kJ of heat. After this, the gas did the work. According to the 1st law of thermodynamics Q=A+∆U (1)

2. ∆U can be found from the equation: ∆𝑈= 3 / 2 𝜈𝑅∆𝑇, since the graph shows the dependence of volume on temperature. It can be seen that the process shown in the figure is isothermal, i.e. T 1 = T 2. And this in turn means that ∆T=T 2 –T 1 =0 and, therefore, ∆U=0.

3. We obtain from (1): A=Q=50 kJ

First version of the task (Demidova, No. 1)

Solution algorithm:

1. We analyze the task and the graph that depicts the gas process.
2. Set the type of process.
3. We determine the work that is performed in this case.
4. We write down the answer.

Solution:

1. From the figure it can be seen that pressure is directly proportional to temperature, i.e. p=αT, Here α – some coefficient. According to the Mendeleev–Clapeyron equation we have:

From here

2. This means that the process is isochoric. With it, the volume does not change.

3. The work of gas is always associated with expansion or compression of the gas, which does not happen in this case. This means that no work is done. It is equal to 0.

Second version of the task (Demidova, No. 8)

A piece of aluminum weighing 5 kg was heated from 20 °C to 100 °C. How much heat was expended to heat it?

Solution algorithm:

1. We write down the formula for determining the amount of heat.
2. We calculate the amount of heat by substituting the values ​​​​given in the condition.
3. We write down the answer.

Solution:

1. The amount of heat Q that is expended to heat the piece is determined by the formula: Q=cmΔt.

2. According to the condition, the body mass is equal to t= 5 kg, the heat capacity of aluminum is c = 900 J/(kg 0 C), and the temperature difference Δt = 100 0 -20 0 = 80 0.

We have: Q= 900∙5∙80= 360000J =360 kJ.

Third version of the task (Demidova, No. 28)

A heat engine with an efficiency of 40% performs useful work of 60 J per cycle. How much heat does the machine receive from the heater per cycle?

Solution algorithm:

1. We write down the efficiency formula for a heat engine.
2. We substitute numerical values ​​and calculate the required amount of heat.
3. We write down the answer.

Solution:

1. Thermal efficiency machine is calculated by the formula:

where Q1 is the amount of heat that the heat engine receives from the heater; A - useful work. According to the condition, A = 60 J. And the efficiency is 40% = 0.4. From the formula we get:

Every person is familiar with the laws of physics, because physical phenomena They are everywhere next to us and it is impossible to neglect them. People each measure their temperature environment, turn on electrical appliances, use the Internet. But all these manipulations contain knowledge about such a science as physics. An excellent specialist in his field, A.V., became an assistant in mastering this subject for grades 7-9. Peryshkin, who prepared a solution book for a school physics textbook.

The author not only fully and clearly reveals all the exercises from the textbook, he also adds the necessary comments to the ready-made answers, which help to better understand the incomprehensible topic from the paragraph. Using the GDZ, the student will discover various algorithms for solving problems and learn to apply them when solving homework and classwork. Also, seventh graders will learn how to correctly formulate their solution and will be able to deal with all laboratory work.

Ready-made answers to the collection of problems for grades 7-9 fully comply with the Federal State educational standards and are recommended for students who are preparing for tests or for the Olympics. GDZ in physics include detailed solutions to more than 1800 problems. The material is presented in a fairly accessible form that will be understandable to students of any level of training. GDZ in physics for grades 7-9, collection of problems Peryshkin reveals the essence school textbooks Peryshkin for grades 7, 8 and 9.

The manual is divided into parts that correspond to the seventh, eighth and ninth years of study. Seventh grade involves studying topics such as the structure of matter; interaction of bodies; pressure solids, liquids and gases; work, power and energy. Seventh graders have to figure out the basics mechanical movement, learn to calculate the path and time of movement. They will also learn to solve problems per unit mass and calculate the density of substances. Students will become familiar with the phenomenon of gravity and the force of gravity. They can easily solve all problems using Hooke's law. Seventh graders will learn about a dynamometer and be able to add two forces directed in the same straight line. And at the end of the physics course for the seventh grade, students will study the paragraph devoted to the force of friction.

The eighth grade will bring with it knowledge in such sections as: thermal phenomena and possible changes state of aggregation substances; electrical and electromagnetic phenomena; interesting light phenomena. Eighth graders will acquire knowledge of thermal motion, conduction, convection, and radiation. Students solve all problems on the law of conservation and transformation of energy in mechanical and thermal processes. Next, they will get to know the conductors and non-conductors of electricity. Students will understand and remember the formula for current, electrical voltage and resistance, work and power. In 8th grade the topic will be covered magnetic field Earth and the question of the source of light and the law of refraction is sanctified.

The ninth grade includes school curriculum paragraphs on topics: laws on the interaction and movement of bodies; mechanical waves and vibrations, as well as sound; electromagnetic fields; structure of the atom and its nucleus. Initially, ninth graders will deal with material points and a reference system. Next, they will solve problems on the topics of acceleration, speed and displacement. They will work through Newton's first and second laws and understand rectilinear and curvilinear motion. Students will become familiar with the basics of oscillations and waves. They will be able to learn to recognize the direction of current and the direction of its magnetic field lines. And at the end of the course, ninth graders will understand how to use the energy of atomic nuclei. GDZ contribute to the manifestation of the child’s independence, they also develop analytical ability and logical thinking. The manual gives knowledge about theories and laws, teaches the correct sequence in solving problems. Such a collection will help students significantly improve their academic performance and not be afraid of monitoring knowledge at school.

GDZ for a physics textbook for grade 7 Peryshkin A.V. can be downloaded.