Crossword puzzle on the topic of inertia. Crosswords - a teaching aid in physics. What you should know

It's enough to go yourself. If you move away from the house, it will begin to move away from you. To move away means to move. The building will begin to move relative to you.

Let's pose the question differently. Can you make a house move not relative to itself, but relative to some other body, for example the Earth, surrounding trees, etc.? Hardly. Now this will require such a significant action that you will not succeed. But of course the building will not move relative to the Earth.

A body at rest relative to the Earth will maintain its state of rest until other bodies remove it from this state For example, a ball lying on the ground will begin to move when another ball hits it or is kicked. In the absence of the action of other bodies, the ball will not move relative to the Earth and will continue to remain in its place.

Reducing the speed of a moving body and stopping it also does not happen by itself. This also requires the action of other bodies. For example, the speed of a bullet passing through a board is reduced by the action of the board on it; a rolling ball stops due to friction with the ground, etc.

A change in the direction of speed also occurs under the influence of any bodies. For example, a thrown ball changes direction when it hits a wall or hand. A fast running person, in order to go around a tree, grabs it with his hand (Fig. 13).

Figure 13. The need for action of bodies to change the speed of another body.
So, To change the speed of a body relative to the Earth, the action of other bodies is necessary.

Is the action of other bodies necessary to maintain the speed of the body constant?

In the 4th century. BC e. The ancient Greek scientist Aristotle wrote that “everything that moves is necessarily moved by something.” This means that to maintain motion, the constant action of some other body is necessary. For example, in order for a cart to move, it must be constantly pulled by a horse. If it stops pulling, the cart will stop. The reason for the movement lies in the action exerted on given body some other body, - this is what Aristotle and his followers believed.

Aristotle's scientific legacy is enormous. It consists of numerous works on logic, physics, philosophy, biology, psychology, history, aesthetics, ethics, politics, etc. Alexander the Great, who had the opportunity to study with Aristotle, spoke of his teacher this way: “I honor Aristotle along with my father, because if I owe my life to my father, then to Aristotle I owe everything that gives it value.”

Aristotle's authority was so high that his views on the causes of the motion of bodies remained dominant in science for two thousand years! And only in the 17th century, mainly thanks to the research of Galileo, it became clear that Aristotle’s theory was erroneous.

It was found that uniform and rectilinear movement can occur in the absence of the action of any bodies.

Why then does the cart stop when the horse stops pulling it? It stops not because it is unable to move on its own, but because its movement is impeded by an action earth's surface(friction on the ground). If there were no resistance to movement, then it would continue to move with constant speed and without a horse. By the way, one of the first to understand this was the contemporary of Aristotle, the Chinese philosopher Mo Tzu. Even then he wrote: “If there is no opposing force, the movement will never stop. This is as true as the fact that a bull is not a horse.” However, the teaching of this philosopher did not last long. Already in the 2nd century. BC e. it was completely forgotten.

Figure 14. Trolley experiment.
Consider the following experiment. A board is installed at an angle on the table. Sand is poured on the surface of the table. The cart is placed on the inclined board and released. The cart, having rolled onto the table and hit the sand, quickly stops (Fig. 14, a). The reason for the stop is the resistance provided by the sand.

Let's reduce the resistance by leveling the sand. Having moved from the previous height, the cart will now travel a greater distance before stopping (Fig. 14.6). If you completely remove sand from the path of the cart, then it will travel an even greater distance before stopping (Fig. 14, c). Therefore, than less action another body onto the cart, the slower the speed of its movement changes, the closer its movement is to uniform.

How will a body move if other bodies do not act on it at all? Galileo gave the answer to this question. He wrote: “When a body moves along horizontal plane, without encountering any resistance to movement, then... its movement is uniform and would continue indefinitely if the plane extended in space without end.”

Galileo justified his conclusion as follows: “When moving along inclined plane downwards there is an acceleration, and when moving up there is a deceleration. It follows from this that the horizontal movement is unchanging, because... it is not weakened by anything, does not slow down or accelerate.”

Movement that is not supported by any bodies is called movement by inertia.

Any body brought out of a state of rest by some bodies continues to move by inertia after the action of these bodies ceases.

Motion by inertia is the basis of the principle of operation of artillery shell fuses. When a projectile, having hit an obstacle, stops abruptly, the explosive capsule, located inside the projectile, but not rigidly connected to its body, continues to move by inertia. When it hits the fuse tip, an explosion occurs.

Under terrestrial conditions, due to friction and resistance of the medium, inertial movement occurs at a decreasing speed. After turning off the engine, the car continues to move, but its speed becomes less and less, and after a while it stops. After leaving the rifle, the bullet moves by inertia, but due to air resistance, its speed gradually decreases.

Figure 15. Motion by inertia.
In the absence of the action of other bodies, motion by inertia is uniform and rectilinear, that is, it occurs at a speed that does not change either in magnitude or direction. This is exactly how, for example, a rocket would move far from everyone celestial bodies after turning off the engines. She would continue to fly at the speed that was communicated to her before.

Figure 16. Straight and uniform motion by inertia.

Questions.

1. What kind of movement is called movement by inertia?

2. Give examples of motion by inertia.

3. Considering the movement of a body on an absolutely smooth surface (without friction), Galileo came to the conclusion that “if, after a body falls along any inclined plane, a rise occurs, then... it rises to the same degree of elevation or height above the horizon... .and not only in the case when the planes have the same inclination, but also in the case when they form different angles.” What conclusion can be reached if we continue this reasoning based on Figure 15?

4. At one of the banquets, Colonel Zillergut, a character in J. Hasek’s novel “The Adventures of the Good Soldier Švejk,” told, among others, the following story: “When the gasoline ran out, the car was forced to stop. I also saw this myself yesterday. And after that they still talk about inertia, gentlemen!.. Well, isn’t it funny?” Does the story told by Colonel Zillergut contradict the idea of ​​inertia? Why?

5. Figure 16 shows how to attach the hammer to the handle. Explain it.

6. In which direction does a tripping person fall? a person who slipped? Why?

7. How did the speed of movement of the cars shown in Figures 17, a and 17.6 change: did it increase or decrease?

Figure 17. Change in car speed.

Submitted by readers from Internet sites

Online library with textbooks and books, lesson plans for 7th grade physics, books and textbooks according to the 7th grade physics calendar planning

Lesson content lesson notes supporting frame lesson presentation acceleration methods interactive technologies Practice tasks and exercises self-test workshops, trainings, cases, quests homework discussion questions rhetorical questions from students Illustrations audio, video clips and multimedia photographs, pictures, graphics, tables, diagrams, humor, anecdotes, jokes, comics, parables, sayings, crosswords, quotes Add-ons abstracts articles tricks for the curious cribs textbooks basic and additional dictionary of terms other Improving textbooks and lessonscorrecting errors in the textbook updating a fragment in a textbook, elements of innovation in the lesson, replacing outdated knowledge with new ones Only for teachers perfect lessons calendar plan for the year guidelines discussion programs Integrated Lessons

Physics teacher

Slide 2

What you should know

  1. How can you change the speed of a body?
  2. How to change the direction of body movement?
  3. Under what conditions does the speed of a body not change?

  • Slide 3

    How can you change the speed of a body?

    The speed of a body changes if other bodies act on it!!!

    Slide 4

    How can you change the direction of a body's speed?

    The direction of a body's velocity changes if other bodies act on it!!!

    Slide 5

    How does the change in the speed of a body depend on the magnitude of the action of another body?

    The less the action of another body, the longer the speed of movement is maintained and the closer the movement is to uniform!!!

    Slide 6

    This pattern is also true for bodies moving in a train, plane, etc.

    Slide 7

    • To understand the laws of nature is our goal!
    • Aristotle in the 4th century. BC. observing the movement of bodies, he believed that there is no action, which means there is no movement.
    • “Everything that is in motion moves due to the influence of another body. Without action there is no movement."
    • This idea dominated science for more than 2000 years.
    • Galileo Galilei in the 17th century. used the experiment: the movement of a ball on an inclined plane.
    • Conclusions: The body moves uniformly and rectilinearly if all influences are removed. “A body that is not acted upon by other bodies moves at a constant speed.”
    • G. Galileo made a mistake in believing that a free body should move in a circle (he observed the Moon).
    • What did he not take into account?

  • Slide 8

    How will a body move if no other bodies act on it?

    • The phenomenon of maintaining the speed of a body in the absence of the action of other bodies on it is called inertia.
    • It has been established experimentally: If a body is not acted upon by other bodies, then it is either at rest or moves rectilinearly and uniformly relative to the Earth.

  • Slide 9

    • Isaac Newton in the 17th century. put a final point in solving a centuries-old problem, he formulated the law of Inertia:
    • “If a body is not acted upon by other bodies, then it is in a state of rest or uniform linear motion.”

    Useful:

    • The phenomenon of inertia in a medical thermometer;
    • Attaching the hammer to the handle;P
    • Dust from the carpet;
    • Space rocket in orbit;
    • A tram, an electric train, a car with the engine turned off, a cyclist.
    • Accidents, collision with a pedestrian;
    • In equestrian sports;
    • The machine is turned off.

  • Slide 10

    If the body is not acted upon by other bodies,

    then it moves at a constant speed

    Slide 11

    Check yourself!

  • Slide 12

    Choose one correct answer!

    1. What is inertia?
    D. The ability of a body to maintain speed.
    U. The phenomenon of conservation of the speed of a body in the absence of the action of other bodies on it.
    B. Change in the speed of a body under the influence of other bodies.
    2. What happens to the block if you sharply pull the thread?
    C. Will fall back.
    D. Will fall forward.
    E. Remains motionless.
    3. In what case is the manifestation of inertia observed?
    A. The stone falls to the bottom of the gorge.
    P. Dust is knocked out of the carpet.
    N. The ball bounced off the wall after being hit.
    4. Why do they take a run-up when long jumping?
    K. To jump higher.
    L. To increase the length of the trajectory of the body.
    X. To gain speed for the push.

    Crossword puzzle on the subject "physics" on the topic " State of aggregation substances"

    Horizontally

    2. This is a process in which a transition occurs from a liquid to a solid, which occurs with the release of heat into the environment

    6. The process of transition from gas to solid state, bypassing the liquid phase is

    8. This is the process by which a transition occurs from gas to liquid state, which occurs with the release of heat into the environment

    Vertically

    1. The phenomenon of converting liquid into vapor is called

    3. This process is called reverse sublimation

    4. Which device determines the amount of moisture in the air (the device consists of two thermometers)

    5. This is the process of transition of matter from solid state into liquid with heat absorption

    7. Vaporization that occurs from the surface of a liquid is called

    Answers

    Crossword puzzle on the subject "physics" on the topic "Interaction of bodies"


    Horizontally

    4. Temperature unit?

    5. device for measuring arm muscle strength

    9. Solids, whose molecules are arranged in a certain order

    12. The phenomenon of conservation of the speed of a body in the absence of the action of other bodies on it

    15. Microgravity

    17. The line along which the body moves

    20. Value showing the change in speed over time

    23. Who was the first to point out the existence of inertia

    25. Changes occurring with bodies and substances in the surrounding world

    Vertically

    1. A device used for terrain orientation

    2. The state of aggregation of a substance in which it has its own shape and volume

    3. Interference is obstructive relative motion bodies in contact

    6. Everything that exists in the Universe regardless of our consciousness

    7. a physical quantity that is equal to the ratio of body mass to its volume

    8. Temperature measuring device?

    10. A phenomenon in which mutual penetration of molecules of one substance occurs between the molecules of another

    11. The state of aggregation of a substance in which it does not have its own shape and constant volume. Takes the shape of the vessel and completely fills the volume provided to it

    13. The movement of a body during which it travels equal distances in equal periods of time

    14. Everything that exists in the Universe regardless of our consciousness

    16. Attraction

    18. Guess about how the phenomenon occurs

    19. Who was the first to point out the existence of inertia?

    21. Value characterizing the speed of movement and direction of movement material point relative to the chosen reference system

    22. The scientist who discovered the basic laws of motion of bodies and the law of universal gravitation?

    24. What is the name of the science about the simplest and at the same time the most general laws of nature, about matter, its structure and movement?

    Answers


    Crossword puzzle on the subject of "physics" on the topic "Pressure"


    Horizontally

    3. The air shell of the earth

    4. Who was Magderburg von Guericke, who performed the experiment that convinced everyone of the existence of atmospheric pressure

    5. What is the force of pressure?

    6. What is used on the tractor to reduce pressure on the soil.

    8. What law is used when constructing hydraulic machines?

    9. The pressure exerted by a fluid at rest is called...

    10. In which communicating objects the surface of the liquid is at the same level

    12. Ancient Greek scientist, mathematician and mechanic

    13. The ratio of the modulus of the pressure force acting on a certain surface area to this area

    14. Unit of pressure in si

    15. These are devices driven by compressed air.

    16. What instrument can be used to apply great pressure to a pinched body?

    17. Area where clear or partly cloudy weather prevails

    18. A huge atmospheric vortex with a diameter of hundreds and even thousands of kilometers

    20. Device for measuring liquid or gas pressure

    21. The unit of measurement for atmospheric pressure is mm. mercury...

    22. Device for measuring atmospheric pressure

    Vertically

    1. What should be used when bolting wooden parts together.

    2. Vessels that have a common part connecting them are called...

    7. Device for measuring atmospheric pressure.

    8. Physical quantity on which pressure depends.

    9. A machine designed to compress bodies is called...

    11. When what increases, the gas pressure increases

    15. What is less of a liquid whose level is higher in a communicating vessel?

    19. Underwater vehicle for oceanographic and other research at great depths

    Answers