Purpose of the test
The technique is intended to evaluateknowledge , under the section "Mechanics". The material is intended forstudents first year SPO.
Test instructions
The time given to complete the test is exactly60 min. Don't stay too long on one task. Perhaps you are on the wrong path and it is better to move on to the next task. But don't give up too easily; Most tasks can be solved if you show a little persistence. The answer to the task consists of choosing what you think is the correct answer. Sometimes you need to choose from several options. Write your answer in the space indicated. If you are not able to solve the problem, you should not write the answer at random. The test does not contain “tricky” tasks, but you always have to consider several solutions. Before you begin your solution, make sure you understand exactly what is required of you. You will waste your time if you take on a solution without understanding what the problem is.
Registration of works
You need to write down the answers to the test in your test notebooks in the form:
1 a
2 a,b
MECHANICAL TASKS
a) moving
b) trajectory
c) line of movement
a) coordinate system
b) body of reference
c) watch
d) moving a point
a) moving
b) travel time
c) distance traveled
b) he is short.
5. The clock system does:
a) rotational movement
b) forward movement
c) straight movement
a) 11 m/s
b) 9 m/s
c) 1 m/s
a) moving.
b) instantaneous speed
c) body coordinates
d) acceleration
a) constant in direction
b) constant in modulus
a) -2 m/s
b) 2 m/s
c) 50 m/s
a) kinematics
b) dynamics
c) static
a) inertia
b) inertia
c) uniformly accelerated motion
A ) Newton's first law
b) Newton's second law
c) Newton's third law
a) internal structure
b) features of the external environment
a) fly
b) person
c) trolleybus
a) movements
b) acceleration
c) application of force
a) 0.5 m/s2
b)200 m/s2
c)2 m/s2
a) -20 N
b) 0 N
c) 40 N
19. The gravitational constant G is equal to:
a)6.67x10
b)6.67x10
c)9.8
a) elastic force
b) gravity
c) body weight
a) overload
b) weightlessness
c) free fall
a) gravity
b) body weight
c) elastic force
a) gravity
b) elastic force
c) body weight
d) equal to gravity
a) 1 m/s
b) 2 m/s
c) 0 m/s
a) with the ground
b) with vacuum
27. The work done by the force F is positive if the angle between the vector F and S:
A)
b)
V)
a) 3 s
b) 40 s
c) 160 s
a) 50 J
b) 200J
c)2000J
a) 10 J
b) 100 J
c)1000 J
a) kinetic energy
b) potential energy
c) mechanical work
a) 2000 J
b) 10000 J
c) -2000 J
a)0.5 m/s
b)1.5 m/s
c)2 m/s
a)0.5 J
b)2 J
c)5000 J
a) 0.4 N
b) 2.5 N
c)10 N
a) 98 kg
b)100 kg
c)9800 kg
A ) 0.1 m/s
b) 10 m/s
c) 90 m/s
a) 0 m
b) 2.5 m
c) 5 m
39. The equation for determining the coordinates of a material point has the form Determine the acceleration using it.
a) -3 m/s2
b)4 m/s2
c)8 m/s2
a) uniform
b) uniformly accelerated
c) equally slow
Key to the test
1. The line along which a point of the body moves is called -
a) moving
b) trajectory
c) line of movement
2. What forms the reporting system.
a) coordinate system
b) body of reference
c) watch
d) moving a point
3.What does a taxi passenger pay for:
a) moving
b) travel time
c) distance traveled
4. A cyclist is riding along the road. In what case can it be considered as a material point:
a) he moves without stopping for 60 meters.
b) he is short.
c) he travels a distance of 60 km.
5. The clock system does:
a) rotational movement
b) forward movement
c) linear motion
6. The train is traveling at a speed of . A passenger walks against the movement of the train at a speed of 1 m/s, relative to the carriage. Determine the passenger's speed relative to the ground.
a) 11 m/s
b) 9 m/s
c) 1 m/s
7. The process of changing the speed of a body is characterized by:
a) moving.
b) instantaneous speed
c) body coordinates
d) acceleration
8. Motion with acceleration is called uniformly accelerated:
a) constant in direction
b) constant in modulus
c) constant in direction and module
9. The speed of a car changes from 20m/s to 10m/s in 5 seconds. Determine the acceleration of the car.
a) -2 m/s
b) 2 m/s
c) 50 m/s
10. Using the equation x=x you can determine:
a) movement during uniformly accelerated motion
b) coordinates of the body during uniform motion
c) coordinates of the body during uniformly accelerated motion
11. The section of mechanics that studies the laws of interaction of bodies is called:
a) kinematics
b) dynamics
c) static
12. The phenomenon of maintaining the speed of movement of a body in the absence of external influences is called:
a) inertia
b) inertia
c) uniformly accelerated motion
13. Which of Newton’s laws has the following formulation: there are such reporting systems relative to which a translationally moving body maintains its speed constant if other bodies do not act on them, or their actions are compensated.
a) Newton's first law
b) Newton's second law
c) Newton's third law
14. The reason for changing the speed of a body is:
a) internal structure
b) features of the external environment
c) interaction with other bodies
15. Which body is more inert:
a) fly
b) person
c) trolleybus
a) movements
b) acceleration
c) application of force
17. For a body weighing 10 kg. a force of 20N is applied. Determine the acceleration with which the body is moving.
a) 0.5 m/s2
b)200 m/s2
c)2 m/s2
18. A weight acts on the scales with a force of 20 N. What force does the scales exert on the weight?
a) -20N
b) 0 N
c) 40 N
19. Gravitational constantGis equal to:
a)6.67x10
b)6.67x10
c)9.8
20. The force with which the body acts on horizontal support or vertical suspension is called:
a) elastic force
b) gravity
c) body weight
21. The disappearance of weight when the support moves with free fall acceleration is called:
a) overload
b) weightlessness
c) free fall
22. Using this formula you can determine:
a) gravity
b) body weight
c) elastic force
23. The force arising as a result of deformation and directed in the direction opposite to the movement of body particles during deformation is called:
a) gravity
b) elastic force
c) body weight
24. Choose all the correct answer options. Friction force:
a) equal in magnitude to the external force
b) directed in the direction of body movement.
c) directed in the opposite direction of movement
d) equal to gravity
25.Two carts with masses of 200 kg each. moving towards each other at speeds of 1m/s. At what speed will they move after an inelastic impact?
a) 1 m/s
b) 2 m/s
c) 0m/s
26. What does a rocket interact with when moving:
a) with the ground
b) with vacuum
c) with gases formed during combustion.
27. Work done by forceF, is positive if the angle between the vectorFAndS:
A)
b)
V)
28. A crane with a power of 2 kW performed 0.08 MJ of work. How long did the work take to complete?
a) 3 s
b) 40With
c) 160 s
29. Determine the potential energy of a person weighing 100 kg at a height of 2 meters
a) 50 J
b) 200J
c)2000J
30. Determine the kinetic energy of a bullet weighing 2 grams flying at a speed of 100 m/s.
a) 10 J
b) 100 J
c)1000 J
31. The formula allows you to determine:
a) kinetic energy
b) potential energy
c) mechanical work
32. The kinetic energy of the body changed from 4000J to 6000J. Determine the work of the body:
a) 2000 J
b) 10000 J
c) -2000 J
33. A railway car weighing 15 tons moves at a speed of 2 m/s and catches up with a stationary car weighing 5 tons. What will be the speed of the cars after their collision?
a)0.5 m/s
b)1.5m/s
c)2 m/s
34. A sled moving uniformly under the influence of a force of 50 N moved 100 meters. What kind of work do they do?
a)0.5 J
b)2 J
c)5000 J
35. Determine the force exerted by a body weighing 5 kg. Acquires an acceleration of 2m/s?
a) 0.4 N
b) 2.5 N
c)10 N
36. Determine the mass of the body if the force of gravity is 980 N.
a) 98 kg
b)100kg
c)9800 kg
37. A car, moving uniformly, covered 30 meters in 3 seconds. Determine its speed.
a) 0.1 m/s
b) 10m/s
c) 90 m/s
38. The boy threw the ball to a height of 2.5 m and caught it again. Determine the movement of the ball.
a) 0 m
b) 2.5 m
c) 5 m
39. The equation for determining the coordinates of a material point has the form. Use it to determine the acceleration.
a) -3 m/s2
b)4 m/s2
c)8 m/s2
40. The projection of the speed of a moving body changes according to the law. Describe the nature of the movement:
a) uniform
b) uniformly accelerated
c) equally slow
Ticket No. 1
1.Mechanical movement. Relativity of motion. Uniform and uniformly accelerated linear motion.
Mechanical movement is called the change in the position of a body in space relative to other bodies over time.
Examples: the movement of a car, the Earth around the Sun, clouds in the sky, etc.
Mechanical movement relatively: a body can be at rest relative to some bodies and move relative to others. Example: a bus driver is at rest relative to the bus itself, but is in motion with the bus relative to the ground.
To describe mechanical motion, a reference system is chosen.
Reference system is called a body of reference, an associated coordinate system and a device for measuring time (for example, a clock).
In mechanics, the body of reference is often the Earth, to which a rectangular Cartesian coordinate system (XYZ) is associated.
The line along which a body moves is called trajectory.
Straightforward is called movement if the trajectory of the body is a straight line.
The length of the trajectory is called by. The path is measured in meters.
Moving is a vector connecting the initial position of the body with its final position. Designated and measured in meters.
Speed is a vector quantity equal to the ratio of movement over a short period of time to the value of this interval. Designated and measured in m/s.
Uniform This is a movement in which a body travels the same distance in any equal intervals of time. In this case, the speed of the body does not change.
During this movement, displacement and speed are calculated using the formulas:
If a body travels unequal paths in equal periods of time, then the motion will be uneven.
With such movement, the speed of the body either increases or decreases.
The process of changing the speed of a body is characterized by acceleration.
Acceleration is a physical quantity equal to the ratio of a very small change in the velocity vector ∆ to a small period of time ∆t during which this change occurred:.
Acceleration is indicated by a letter and is measured in m/s 2 .
The direction of the vector coincides with the direction of change in speed.
In uniformly accelerated motion with an initial speed, the acceleration is equal to
Hence the speed of uniformly accelerated motion is equal.
Displacement during rectilinear uniformly accelerated motion is calculated by the formula:
2. Laboratory work “Estimating the mass of air in a classroom using the necessary measurements and calculations.”
We will find the mass of air using the formula: , where is the volume of the classroom.
The air density under normal conditions is 1.29 kg/m 3 (from the tables of Rymkevich’s collection of problems).
To calculate the volume of a class you need to measure its length a, width b and height c, and multiply the resulting values:
Knowing the density and calculated volume, you can find the mass of air using the above formula.
3.Task on the application of the law of electromagnetic induction.
Ticket number 2
1. Interaction of bodies. Force. Newton's laws of dynamics.
Change in body speed, i.e. the appearance of acceleration is always caused by the influence of any bodies on a given body.
Force is a vector physical quantity that is a measure of the acceleration acquired by bodies during interaction.
The force is characterized by its modulus, point of application and direction.
Force is designated and measured in Newtons (N)..
If several forces act on a body at the same time, then the resulting force is found according to the rule of vector addition.
Newton's laws:
I. (Law of inertia). There are such reference systems (inertial), relative to which translationally moving bodies retain their speed constant if they are not acted upon by other bodies or the action of other bodies is compensated.
II. The product of body mass and acceleration is equal to the sum of all forces acting on the body.
III. The forces with which the bodies act on each other are equal in magnitude and directed in one straight line in opposite directions.
Laboratory work No. 2.
Measuring the average speed of a body
Determination of body acceleration
Goal of the work:– master the practical skills of measuring the speed of a body by the magnitude of its movement and the time of movement;
– work out a practical technique for determining the acceleration of a body from its displacement and time of movement.
Equipment: stopwatch, gutter, steel ball, metal block, gutter support, stacking case.
Theoretical part.
1. Uniform straight motion. Average speed.
When considering the movement of any bodies, we always note: by plane get to the right place much faster than by train; the car moves faster than the cyclist, etc.
The movement of different bodies occurs at different speeds.
To characterize the speed and direction of movement of a body, a vector quantity called speed.
Uniform linear movement - the simplest type of mechanical motion in which a material point makes identical movements over any equal periods of time. This is a movement with a constant speed in magnitude and direction. With uniform motion, speed shows how far the body has traveled per unit time.
Speed is indicated by the letter V, and the time of movement is a letter t. Thus, the speed of a body during uniform motion is a quantity equal to the ratio of the path to the time during which this path is covered:
https://pandia.ru/text/78/430/images/image005_78.gif" width="147" height="51 src="> or . (1)
In SI, the basic unit of speed is m/s (meter per second): [V]=[m/s]. The speed of uniform motion equal to 1 m/s shows that a body covers a path 1 m long in 1 s. [V] = [m/s] is a derived unit, it is obtained according to the speed formula by substituting instead of the physical quantities included in the formula, their units of measurement.
Speed has not only a numerical value, but also a direction. This is very important for determining the location of the body at a certain point in time. If you know that the car was on the road for 2 hours, moving at a speed of 60 km/h, then you can determine that it traveled 120 km, but you will not be able to say where exactly the car ended up, since the direction of movement was not indicated. By specifying the direction, it becomes possible to fix the position of a moving body in space. Speed is a vector quantity. Knowing the speed, you can find movingS for any period of time t:
The direction of the velocity vector coincides with the direction of the displacement vector. The direction of the velocity vector is the direction of motion of the body.
When calculating, they do not use the velocity vector itself, but its projection onto the axis. Projections of vectors are scalar quantities, so algebraic operations can be performed with them.
When uneven (variable) movement differentiate instant And average speed. A movement in which a body makes unequal movements at equal intervals of time is called uneven movement.
 |
In Fig. Figure 1 shows the positions of the sleds, which first roll down an inclined plane (the icy surface of a slide), and then move along a horizontal section at regular intervals. Comparing the movements of the sled over equal periods of time, we see that when the sled rolls down an ice slide, the distance between them increases, therefore, the speed of the sled increases. Having rolled down the hill, the sled gradually slows down its movement - the distance covered by the sled decreases over equal periods of time.
With uneven movement, a body makes unequal movements in equal periods of time. The speed of such movement varies from point to point of the movement trajectory. To characterize variable (uneven) motion, the concept is used average speed.To find the average soondistance on a given section of the path (or in a given time) must be coveredThe path taken by the body is divided by the time of its movement:
or .
(3)
If the body passes sections of the path https://pandia.ru/text/78/430/images/image013_34.gif" width="27" height="25 src=">.gif" width="21" height="25 src="> respectively for the time https://pandia.ru/text/78/430/images/image019_25.gif" width="16" height="25 src=">, then the average speed
. (4)
For example, when getting to school, you use a trolleybus, metro, and walk part of the way. To calculate the average speed of your movement (over a given section of the journey or for a given period of time), you need to know how much time you spend at each stage of the movement, and the path that corresponds to each section of the movement.
Suppose you walk 300 m to the trolleybus stop and spend 240 s on this path, by trolleybus you travel 2000 m and spend 360 s, by metro the distance is 6000 m and the time is 600 s. Well, off to the store,
leaving the metro, you walk 100 m in 80 s.
In this case, your average speed throughout the entire journey to school is determined as:
But remember: You cannot use average speed values to find the average speed using the arithmetic average method!
For example, the average pedestrian speed (in our case) is ≈1.3 m/s, a metro train has a speed of 36 km/h, which corresponds to ≈10 m/s, a trolleybus speed is ≈20 km/h, which corresponds to ≈5.5 m /With. However Vcp along the entire section of the route - 6.6 m/s, and not 4.5, which could have been obtained when calculating Vcp using the arithmetic mean method:
So this method not applicable, because it does not correspond to the definition of speed as a physical quantity. In addition, you should pay attention to the fact that the numerical value of the same speed in different units of measurement is different. This depends on the choice of unit of measurement (36 km/h and 10 m/s).
Most often, speed is expressed in km/h, but the existing International System of Units requires the ability to convert speed from km/h to m/s and vice versa.
To do this, you need to remember that to convert km/h to m/s, this speed value must be multiplied by 1000 (since there are 1000 m in 1 km) and divided by 3600 (in 1 hour there are 3600 s).
You can also remember that 36 km/h = 10 m/s and subsequently evaluate the value of speed in other units based on proportionality.
For example, 72 km/h=20 m/s; 54 km/h=15 m/s, etc.
Instantaneous speed is the speed at a given point on the trajectory at a given point in time. Instantaneous speed is the limit to which the average speed tends over an infinitesimal period of time:
(5)
The speed of uniform rectilinear motion of a body is its instantaneous speed, since it is the same at any time and at any point in the trajectory.
2. Uneven movement.
The movement of any body in real conditions is never strictly uniform and linear. A movement in which a body makes unequal movements at equal intervals of time is called notuniform movement.
With uneven translational motion, the speed of the body changes over time. The process of changing the speed of a body is characterized by acceleration.
A physical quantity that characterizes the rate of change in speed and is equal to the ratio of the change in speed to the period of time during which this change occurred is called average acceleration:
(6)
If during a period of time a body from a point A trajectory has moved to a point IN and its speed changed from to , then the change in speed over this period of time is equal to the difference between the vectors https://pandia.ru/text/78/430/images/image028_16.gif" width="17" height="28 src=">.gif" width="20 " height="28 src=">.gif" width="15" height="20">.gif" width="23" height="20"> , during which the speed change occurs.
If a body moves rectilinearly and its speed increases in absolute value, i.e. > , then the direction of the acceleration vector coincides with the direction of the velocity vector https://pandia.ru/text/78/430/images/image032_9.gif" width="17" height="25">>, the direction of the acceleration vector is opposite to the direction of the velocity vector https ://pandia.ru/text/78/430/images/image030_12.gif" width="15" height="20 src="> in this case it can be directed at any angle to the velocity vector (Fig. 4).
 |  |
Rice. 2. Fig. 3. Fig. 4.
The simplest type of uneven motion is uniformly accelerated motion. Uniformly accelerated motion with acceleration constant in magnitude and direction is called:
(7)
From the formula it follows that when expressing speed in meters per second and time in seconds, acceleration is expressed in meters per second squared:
Rectilinear motion with constant acceleration, at which
the speed module increases, called uniformly accelerated motion, and rectilinear motion with constant acceleration, at which the speed modulus decreases, is called equally slow.
Let - the speed of the point at the initial moment of time https://pandia.ru/text/78/430/images/image039_8.gif" width="17" height="24 src="> - its speed at any time t. Then, =https://pandia.ru/text/78/430/images/image037_7.gif" width="20" height="28 src=">, and the formula for acceleration will take the form
https://pandia.ru/text/78/430/images/image038_8.gif" width="15" height="25 src="> taken equal to zero, we get
In the case of motion on a plane, vector equation (8) corresponds to two equations for projections of velocity onto the coordinate axes Ox and Oy:
(9)
When moving with constant acceleration, speed changes linearly over time.
The displacement of a body during uniformly accelerated rectilinear motion is described by the vector equation:
(10)
Then the equation for the coordinate of a point during uniformly accelerated motion has the form (in projection onto the Ox axis):
(11)
Where is the coordinate of the body at the initial moment.
With uniformly accelerated motion, the projection of the body’s displacement is related to the final speed by the following formula:
(12)
If the initial coordinate is zero and the initial velocity is also zero, then formulas (9), (11) and (12) will take the following form:
Movement graphs
Practical part.
1 part. In this work we need to determine the average speed of a steel ball rolling down an inclined chute. To do this, it is necessary to find the ratio of the movement made by the body to the time during which it was made.
Part 2. Measure the acceleration of the ball with which it moves along the surface of the inclined chute from a state of rest (the initial speed of the ball is zero). From the equation for uniformly accelerated rectilinear motion it follows that in this case the movement of the ball, acceleration and time of movement are related by the relation: S= at2 /2, where a=2 S/ t2 . Therefore, to determine the acceleration, it is enough to measure the displacement and the time spent on this displacement.
The displacement is determined by the difference between the final and initial coordinates of the ball. Movement time - with a stopwatch.
1. Assemble the experimental setup.
The basis of the experimental setup is a straight trough, one end of which is fixed slightly higher than the other. It is placed on the cover of the stacking module. Place a support under one end of it and adjust its position so that the upper end of the gutter is 3 - 4 mm higher. General form installation is shown in Figure 5.
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The object of observation in the work is a steel ball. The installation can be considered finally configured if the ball rolls from edge to edge of the gutter in 4-5 seconds.
2. Work progress.
To determine the coordinates of the ball, a block and an internal scale on the surface of the groove are used. The block is placed in the groove along the path of the ball. The ball, rolling down the chute, will hit the block. The coordinate of the ball is determined by the position of the edge of the block that it touches at the moment of impact.
Work begins by determining the initial coordinate of the ball. A block and a ball are placed on the gutter 2 - 3 cm from the top edge. The ball should be located above the block. The initial coordinate () is determined by the position of the point of contact between the ball and the block. To do this, it is enough to notice the division of the scale, next to which there is the base of the block, which the ball touches..gif" width="20" height="25 src=">), which it will have after passing the path along the gutter. The value is also entered in Table 1. Having determined the coordinates of the starting and ending points of the movement, calculate its displacement (. S) is determined by the difference between the final and initial coordinates:
The displacement value is entered into Table 1.
Then the ball is released and the stopwatch is started at the same time. Based on the sound of the ball hitting the block, the stopwatch is stopped and its readings are read, which are entered into table 1. Thus, we determined the time of movement of the ball t.
To eliminate random errors, 5 launches are carried out at the same initial and final coordinates. (That is, the movement remains the same.) In this case, the time of movement of the ball will be different (you can turn on (off) the stopwatch a little earlier or a little later). All data is recorded in table 1.
(17)
Then the average speed of the ball is calculated:
Based on the data obtained, the acceleration of the ball is determined:
The results of all measurements and calculations are recorded in Table 1.
Table 1.
Experience no. |
| S, cm | t, With | ||||
In the table: - coordinate of the initial position of the ball; - coordinate of the final position of the ball; S - ball movement; t is the time of its movement; - average travel time; - average speed of the ball; - acceleration of the ball.
3. Task.
Determine the average speed in the first half of the movement trajectory, that is, the path in this case is halved https://pandia.ru/text/78/430/images/image055_4.gif" width="17" height="25 src= "> leave the same, and the final x determined by the formula:
(20)
The base (upper) of the bar is installed next to the division x, the value of which was determined above.
Conduct 5 experiments, measuring the time of movement of the ball along the gutter..gif" width="83" height="55">
The results of all measurements and calculations are recorded in Table 2.
Table 2.
Experience no. |
| ||||||
4. Conclusion.
1.) Comparing the two results, what can be said about the average speed of movement at different parts of the trajectory?
2.) Comparing the obtained acceleration values, conclude whether the motion of the ball along the inclined chute is uniformly accelerated (explain)?
1. Formulate the definition of speed.
2. Formulate the definition of uniform linear motion.
3. Formula for finding speed during uniform linear motion.
4. Formulate a definition of uneven motion.
5. Formulate the definition of average speed and the formula for finding it.
6. Be able to convert speed from km/h to m/s and back.
7. Define instantaneous speed.
8. Formulate the definition of acceleration.
9. Formulate a definition of uneven motion.
10. Formula for finding acceleration during uneven linear motion.
11. Definition of uniformly accelerated and uniformly decelerated motion.
12. Know formulas (8), (9), (10), (11) and (12).
Literature
1. . Ref. Materials: Textbook. A manual for students. - 3rd ed. - M.: Education, 1991. - p.: 6-8; 8-12.
2. . Physics 10th grade: Textbook. for general education institutions.-6th ed., stereotype.-M.: Bustard, 2004. - p.: 32-37; 41-60.
3. . Physics: Textbook. for 10th grade general education institutions/, .-12th ed.-M.: Education, 2004.- p.: 19-21; 24-26; 28-35.
4. . Physics (for non-technical specialties): Textbook. for general education institutions Prof. Education/, .-2nd ed., St.-M.: Publishing Center "Academy", 2003. - p.: 22-25; 26-30.
5. Student's Handbook. Physics / Comp. T. Feshchenko, V. Vozhegova. – M.: Philological Society “WORD”, “AST Publishing House”, Center for the Humanities at the Faculty of Journalism of Moscow State University. , 1998.–p.: 325-329; 388-391; 399-401; 454-455.
Ticket No. 1
Uniformly accelerated motion - motion in which the acceleration is constant in magnitude and direction
a=v-v0/t-t0
a=v-v0/t
A lens is a transparent body bounded by two spherical surfaces. If the thickness of the lens itself is small compared to the radii of curvature of spherical surfaces, then the lens is called thin.
The optical power of a lens is the reciprocal of the focal length of the lens, expressed in meters.
D=1/F=1/d+1/f
D - Optical power of the lens
F - Lens focal length
D- Distance from the object to the lens
F- Distance from lens to image
Ticket 2
1) all bodies consist of particles: atoms, molecules and ions;
particles are in continuous chaotic motion (Thermal);
Particles interact with each other through perfectly elastic collisions.
Main states: Solid, liquid, gaseous, plasma.
Free fall is uniformly accelerated movement without initial speed.
V^2 = 2gh
h=gt^2/2
Gravity acceleration is the acceleration imparted to a body by gravity.
g=GM/r^2
Ticket No. 3
Thermal motion is the process of chaotic (disorderly) movement of particles that form matter.
Brownian motion is the random movement of microscopic visible particles of a solid suspended in a liquid or gas, caused by the thermal motion of the particles of the liquid or gas.
Temperature is a physical quantity that characterizes the thermal state of bodies.
The phenomenon in which mutual penetration of molecules of one substance between the molecules of another occurs is called diffusion.
2) Curvilinear movement is a movement whose trajectory is a curved line (for example, a circle, ellipse, hyperbola, parabola).
Uniform movement in a circle is simplest example curvilinear movement.
l = 2πR
Ticket No. 4
Mechanical motion is a change in the position of bodies in space relative to each other over time.
V= △S/△t
A body of reference is a body relative to which motion is observed.
A reference system is a combination of a reference body, an associated coordinate system and a time reference system, in relation to which the movement of any bodies is considered.
2) Internal energy is the energy of movement and interaction of particles,
of which the body is composed.
Internal energy depends on the temperature of the body, its state of aggregation, chemical, atomic and nuclear reactions
△U=Q-A
Types of heat transfer.
Convection, radiation, thermal conductivity
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Newton's first law - if no forces act on a body or their action is compensated, then this body is in a state of rest or uniform linear motion.
An inertial reference system is a reference system in which all free bodies move rectilinearly and uniformly, or are at rest.
The amount of heat is the change in the internal energy of a body that occurs as a result of heat transfer. It is measured in joules.
The specific heat capacity of a substance shows how much heat is needed to change the temperature of a unit mass of a given substance by 1°C.
Q = c*m*(t2 - t1)
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A trajectory is a line in space along which a body moves.
Movement is a change in the position of a physical body in space.
Path is the length of a section of the trajectory of a material point traversed by it in a certain time.
Inertia is the physical phenomenon of maintaining the speed of a body.
Fuel energy - Different types of fuel of the same mass release different amounts of heat upon complete combustion.
Specific heat of combustion shows how much heat is released during complete combustion
1 kg of this fuel.
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1) The force of gravity is the force of gravitational interaction between bodies with masses. F=G*m1*m2/R^2
Gravity is the manifestation of the force of universal gravitation near the surface of the Earth or on its surface
Body weight is the force with which the body presses on a support or pulls on a suspension.
Weightlessness is a state in which the force of interaction between a body and a support (body weight), arising in connection with gravitational attraction, is negligible.
The transition of a substance from a solid to a liquid state is called melting; The temperature at which this process occurs is called the melting point. The transition of a substance from a liquid to a solid state is called solidification or crystallization. Substances solidify at the same temperature at which they melt.
Specific heat of fusion is a physical quantity that shows how much heat must be imparted to one unit of mass of a crystalline substance in an equilibrium isobaric-isothermal process in order to transfer it from a solid (crystalline) state to a liquid.
Lambda = Q/m
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Force is a vector quantity, which is a measure of the mechanical action of one material body on another.
Mass, a physical quantity, is one of the main characteristics of matter, determining its inertial and gravitational properties.
Newton's second law is that the acceleration a body receives is directly proportional to the force applied to the body and inversely proportional to the mass of the body.
2) Condensation - the transition of a substance into a liquid or solid state from a gaseous state.
Evaporation is the process of phase transition of a substance from a liquid state to a vapor or gaseous state
Saturated steam is in dynamic equilibrium with its fluid. This state is characterized by the fact that the number of molecules leaving the surface of the liquid is equal, on average, to the number of vapor molecules returning to the liquid during the same time.
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Air humidity depends on the amount of water vapor contained in it.
1) Boiling is a process of intense vaporization that occurs in a liquid, both on its free surface and inside its structure.
Friction is a force that occurs when two bodies come into contact and impedes their relative motion.
Ftr= μ Fnorm
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Impulse is a vector physical quantity that is a measure of the mechanical movement of a body
a=v2-v1/△t
The law of conservation of momentum - the vector sum of the impulses of all bodies of the system is a constant value if the vector sum of external forces acting on the system of bodies is equal to zero.
Reactive motion is a movement that occurs when some part of it is separated from the body at a certain speed.
The first law of themodynamics - Energy cannot be created or destroyed (the law of conservation of energy), it only passes from one type to another in various physical processes.
Steam or gas, when expanding, can do work.
In this case, the internal energy of the steam is converted into mechanical energy
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1) Pressure is a physical quantity numerically equal to the force acting per unit area of a surface perpendicular to this surface.
The pressure exerted on a liquid or gas is transmitted to any point in the liquid or gas equally in all directions.
Electric charge is a physical quantity that characterizes the property of particles or bodies to enter into electromagnetic force interactions.
The force of interaction between two point charges in a vacuum is directed along the straight line connecting these charges, is proportional to their magnitudes and inversely proportional to the square of the distance between them.
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Energy - One of the main properties of matter is the measure of its movement, as well as the ability to produce work.
Types of energy: Kinetic, Potential, Electromagnetic
,Gravitational,Nuclear,Chemical,Thermal,Vaakuma.
The law of conservation of energy - energy cannot disappear without a trace or arise from nothing.
The second law of thermodynamics is that the entropy of isolated systems in irreversible processes can only increase, and in a state of thermodynamic equilibrium it reaches a maximum.
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Atmospheric pressure is the pressure of the atmosphere acting on all objects in it and the earth's surface.
Barometer is a device for measuring atmospheric pressure.
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1) Electrostatic field - a field created by electric charges that are stationary in space and unchanging in time (in the absence of electric currents).
Electric field strength is a vector physical quantity that characterizes electric field at a given point and is numerically equal to the ratio of the force (\displaystyle (\vec (F))) acting on a stationary point charge placed at a given point in the field to the magnitude of this charge.
Potential electrostatic field - a scalar quantity equal to the ratio of the potential energy of a charge in the field to this charge.
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1) Ohm's law is an empirical physical law that determines the relationship between the electromotive force of a source or electrical voltage and the current strength and resistance of the conductor, established in 1826, and named after its discoverer Georg Ohm.
Electrical resistance is a physical quantity that characterizes the properties of a conductor to prevent the passage of electric current. R=U/I
When a tog flows through a conductor, a stream of charged particles hits and rubs against the atoms of the conductor.
Depends on both voltage and current.
2) Devices used to transform force and change its direction are called simple mechanisms.
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Current work is the work of an electric field to transfer electric charges along a conductor; The work done by the current on a section of the circuit is equal to the product of the current, voltage and time during which the work was performed.
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1) The wave process (wave) is the process of propagation of vibrations in a continuous medium. Continuous medium- continuously distributed in space and having elastic properties.
A semiconductor is a material that, in terms of its conductivity, occupies an intermediate position between a conductor and a dielectric and differs from a conductor in the strong dependence of its conductivity on the concentration of impurities, temperature and various types of radiation
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1) Photo effect - the emission of electrons by a substance under the influence of light or any other electromagnetic radiation. In condensed (solid and liquid) substances there is an external and internal photoelectric effect
Einstein's formula for the photoelectric effect is the formula:
- expressing the quantum nature of the external photoelectric effect; And
- explaining its main principles.
Light reflection is a physical process of interaction of waves or particles with a surface, a change in the direction of the wave front at the boundary of two media with different properties, in which the wave front returns to the medium from which it came
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1) When a wire carrying current is placed in a magnetic field, the magnetic force acting on the current carriers is transferred to the wire. Let us obtain an expression for the magnetic force acting on an elementary piece of wire of length dl in a magnetic field with induction IN.
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1) If the mass of the entire nucleus is subtracted from the sum of the masses of individual particles of a nucleus, then the remaining value Δm is called the mass defect of this nucleus.
A nuclear reaction is the process of interaction of an atomic nucleus with another nucleus or elementary particle, accompanied by a change in the composition and structure of the nucleus. The consequence of interaction can be nuclear fission, the emission of elementary particles or photons.
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Acceleration is a quantity that characterizes the rate of change in speed.
The movement of any body in real conditions is never strictly uniform and linear. With uneven translational motion, the speed of the body changes over time. The process of changing the speed of a body is characterized by acceleration.
Acceleration is a quantity that determines the rate of change in the speed of a body, and is equal to the limit to which the change in speed tends with an infinite decrease in the time interval Δt:
Uniform motion can be uniformly accelerated or uniformly decelerated.
Uniformly accelerated motion - this is the movement of a body (material point) with positive acceleration, that is, with such movement the body accelerates with constant acceleration. In the case of uniformly accelerated motion, for any equal periods of time, the speed increases by the same amount and the direction of acceleration coincides with the direction of the speed of movement.
∆ And A> 0
Equal slow motion - this is the movement of a body (material point) with negative acceleration, that is, with such movement the body uniformly slows down. In uniformly slow motion, the velocity and acceleration vectors are opposite, and the velocity modulus decreases over time.
¯ ∆ and A 0
In mechanics, any rectilinear motion is accelerated, therefore slow motion differs from accelerated motion only in the sign of the projection of the acceleration vector onto the selected axis of the coordinate system.
Acceleration is measured in meters per second squared
In uniformly accelerated motion with an initial speed of 0, the acceleration is equal to .
where is the speed at time t, then the speed of uniformly variable motion is equal to
0 + t orυ = ±υ 0 ± a t(3.3)
The distance traveled during rectilinear uniformly accelerated motion is equal to the displacement module and is determined by the formula:
where the “plus” sign refers to accelerated motion, and the “minus” sign refers to slow motion.
If the time of movement of the body is unknown, you can use another displacement formula:
where υ is the final speed of movement;
υ 0 – initial speed of movement
The coordinates of a body during uniformly accelerated motion at any time can be determined by the formulas:
where x 0; y 0 – initial coordinates of the body; υ 0 - body speed at the initial moment of time; A– acceleration of movement. The sign “+” and “-” depend on the direction of the OX axis and the direction of the vectors and .
Projection movement
on the OX axis is equal to: S x = x-x 0
on the op axis is equal to: S y = y-y 0
Graph of body displacement versus time at
υ 0 = 0 is shown in Fig. 1.9.
The speed of the body at a given time t 1 is equal to the tangent of the angle of inclination between the tangent to the graph and the time axis υ=tgα.
The graph of the coordinate x(t) is also a parabola (like the graph of displacement), but the vertex of the parabola in the general case does not coincide with the origin. At
A < 0 и х 0 = 0 ветви параболы направлены вниз (рис. 1.10).
The dependence of speed on time is a linear function, the graph of which is a straight line
(Fig. 1.11). The tangent of the angle of inclination of the straight line to the time axis is numerically equal to the acceleration.
In this case, the displacement is numerically equal to the area of the figure 0abc (Fig. 1.11). The area of a trapezoid is equal to the product of half the sum of the lengths of its bases and its height. The bases of the trapezoid 0abc are numerically equal: 0a = υ 0 bc = υ.