Study of uniformly accelerated motion without initial velocity. Study of uniformly accelerated movement without initial speed Laboratory work 1 study of uniformly accelerated movement conclusion

Goals:

Objective: Calculate the acceleration with which the ball rolls down the inclined chute. To do this, measure the length of movement s of the ball for a known time t. Since with uniformly accelerated motion without initial speed

then by measuring s and t, you can find the acceleration of the ball. It is equal to:

No measurements are made absolutely accurately. They are always produced with some error associated with the imperfection of measuring instruments and other reasons. But even in the presence of errors, there are several ways to make reliable measurements. The simplest of them is the calculation of the arithmetic mean from the results of several independent measurements of the same quantity, if the experimental conditions do not change. This is what is proposed to be done in the work.

Means of measurement: 1) measuring tape; 2) metronome.

Materials: 1) gutter; 2) ball; 3) a tripod with clutches and foot; 4) metal cylinder.

Work order

1. Fix the chute with a tripod in an inclined position at a slight angle to the horizontal (Fig. 175). At the lower end of the gutter, place a metal cylinder in it.

2. Launching the ball (simultaneously with the metronome hit) from the top end of the chute, count the number of metronome hits before the ball hits the cylinder. It is convenient to carry out the experiment at 120 beats of the metronome per minute.

3. By changing the angle of the chute to the horizon and making small movements of the metal cylinder, ensure that between the moment the ball is launched and the moment it collides with the cylinder there are 4 beats of the metronome (3 intervals between beats).

4. The movement of the ball along the inclined chute is uniformly accelerated. If we release the ball without initial velocity and measure the distance s traveled by it before the collision with the cylinder and the time t from the beginning of the movement to the collision, then we can calculate its acceleration using the formula: Calculate the time of the ball's movement.

5. Using a measuring tape, determine the length of travel s of the ball. Without changing the inclination of the chute (the conditions of the experiment must remain unchanged), repeat the experiment five times, achieving again the coincidence of the fourth beat of the metronome with the impact of the ball on the metal cylinder (the cylinder can be moved slightly for this).

An example of a job.

Calculations.

Record the conclusion of the work done.

Lesson #3

Relativity of motion

Goals: Introduce students to the law of addition of velocities.

Tasks:

Personal subject tasks:

To form cognitive interests, intellectual and creative abilities of students;

Conviction in the possibility of understanding nature, in the need for the reasonable use of the achievements of science and technology for the further development of human society, respect for the creators of science and technology, attitude towards physics as an element of human culture;

Subject tasks:

Ability to apply theoretical knowledge in physics in practice, solve physical problems for the application of knowledge gained;

Metasubject tasks:

Formation of skills to perceive, process and present information in verbal, figurative, symbolic forms, analyze and process the information received in accordance with the tasks set, highlight the main content of the read text, find answers to the questions posed in it and state it.

Work plan:

organizational stage.

Knowledge update.

Our robot recognized:
Laboratory work 1.

Study of uniformly accelerated motion without initial velocity.

Option I

The purpose of the work: to verify the uniformly accelerated nature of the movement of the bar and determine its acceleration and instantaneous speed.

In this version of the work, the nature of the movement of the bar along inclined plane. Using the device shown in Fig. 146 a of the textbook, it is possible to measure the modules of the vectors of displacements made by the bar over time intervals 1X, /r 2/, /sv - 3/1, ..., 1 i /, counted from the moment the movement began. If we write down their expressions for these displacement vector modules:

O / 2 a a2 / 12 22 sh a3 /,2 Z2

2d2 2 2 3 2 2 2 3

Ag1 atU p2

2 2 2 then you can see the following pattern:

5,: x2:z:...: w 1:22:Z2:...: l2 1:4:9:...: 2-If this pattern is satisfied for the displacement vectors measured in the work, then this will be proof that the movement of the bar along the inclined plane is uniformly accelerated.

An example of a job.

Task I. Study of the nature of the movement of the bar on an inclined plane.

o 1 0.04 o 800 0.10 0.12 o o 00 o 0.20 0.22 0.24 0.26 o o o o o

A O el G
Calculations.

b 3 mm x, 7 mm l-4 15 mm

15,-24sh.24 1 mm, I mm

6 36mm 50mm x65mm x9 82mm

Yu 102mm M and 126mm 1LG 5 146mm

102.5 1mm 5 1mm

I 170mm I t 5.4 198mm tc 227mm::7

1mm, 1mm 5, 1mm

From here we find:

X: 2: x3: 5,: a: 56 1H m: p: 12:!: and - 1: 3: 7: 15: 24: 36: 50: 65: 82: 102: 126: 146: 170: 198 :227. This pattern is not very different from the theoretical pattern for uniformly accelerated motion. Thus, we can assume that the movement of the bar along the inclined plane is uniformly accelerated. Task 2. Determination of the acceleration of the movement of the bar.

Acceleration will be calculated by the formula: a --.

/1o 0.2s; o102mm 0.102m; a1-1 5.1m/s2.

/.5 0.3 s; .5 227 mm 0.227 m; a, 2227m w 5>04 m/s2.

5.m/s2+5.04n/s25 ,

Task 3. Determining the instantaneous speed of the bar at different points in time and plotting the dependence of the instantaneous speed y on time /.

The value of the instantaneous speed will be calculated by the formula: V a. I - 0.1 s; V 5.07 m/s2 0.1 s 0.507 m/s. I 0.2 s; V 5.07 m/s2 0.2 s 1.014 m/s. I - 0.3 s; V - 5.07 m/s2 0.3 s - 1.521 m/s. Graph of instantaneous velocity V versus time I. V, m/s

Additional task. Plotting the brueck's x-coordinate vs. time /. o 0. o 0,xXO Zk1 1,2,3,...,15.

Option 2.

The purpose of the work: to determine the acceleration of the ball and its instantaneous speed before hitting the cylinder.

The movement of the ball along the inclined chute is uniformly accelerated. If we release the ball without initial velocity and 1 gme-rnm the distance 5 it traveled before the collision with the cylinder and the time from the beginning of the movement to the collision, then we can calculate its acceleration using the formula:

Knowing the acceleration a, we can determine the instantaneous speed V by the formula:

An example of a job.

Number of metronome beats n Distance.V. m Time of motion L s Acceleration а -г-, m/s Г Instantaneous velocity а/, m/s

3 0.9 1.5 0.8 1.2

Calculations.

I 0.5 s 3 1.5 s; about -12. 0.8 i/s2; 0.5s2

V 0.8 m/s2 1.5 s -1.2 m/s.

This presentation, pptx format, consists of 16 slides, contains an animation of the experiment; detailed progress of the work; contains test questions; questions of updating knowledge, homework (textbook by A.S. Peryshkin); table and formulas for calculating acceleration and instantaneous speed.

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Slides captions:

Social network of educators site Presentation for a lesson in grade 9 Author: Aprelskaya Valentina Ivanovna Physics teacher MBOU "Secondary School" No. 11p. Ryzdvyany, Stavropol Territory Laboratory work No. 1 Study of uniformly accelerated motion without initial speed

Investigation of uniformly accelerated motion without initial velocity Purpose: to determine the acceleration of the ball and its instantaneous velocity before hitting the cylinder. Laboratory work No. 1, grade 9

Review What is acceleration? What is the direction of the acceleration vector? What are the units for expressing acceleration? What movement is called uniformly accelerated? What equation is called the equation of motion?

We repeat How is the displacement projection calculated for uniformly accelerated motion? How is the displacement projection calculated at V o \u003d 0? How to calculate the projection of the instantaneous velocity vector? What formula is used to calculate the instantaneous speed at V o \u003d 0?

Homework. Textbook: A.V. Peryshkin, E.M. Gutnik. Physics Grade 9 Repeat § 7 (displacement with uniformly accelerated motion), - retelling; § 8, p. 31 repeat formulas, definitions from § 1 - § 6; prepare for a physical dictation on the topic: "Kinematics of uniform and uniformly accelerated motion" 09/23/2014 We write down

Work No. 1. Measuring the acceleration of a body during rectilinear uniformly accelerated motion Purpose: _______ (formulate independently) Equipment: _____ (describe, standing on the table) 09/23/2014 We draw up

We carry out in the following order 1. Assemble the installation according to the drawing, mark the initial position of the ball

Order of execution 2 . Having launched the ball, measure the time of movement until it collides with the cylinder, write it down.

Order of execution 3 . Measure the displacement modulus, record. S

Procedure 4. Without changing the inclination of the chute, repeat the experiment

Order of execution 5 . Record the results of measurements in the table, calculate the average value of the time Experiment No. Displacement module, m Movement time, s Average movement time, s Acceleration, m / Instantaneous velocity V= at , m/s 1 2 Experience No. Displacement module, m Movement time, s Average time of movement, s Instantaneous velocity V= at , m/s 1 2

Order of execution 6. Determine the acceleration using the formula 7. Calculate the instantaneous speed using the formula V = at Note. Since V o \u003d 0, then cf cf

We write down 7. Conclusion on the purpose of the work, taking into account the error in measuring physical quantities Note. Instructions for calculating measurement errors on page 2 71 of the textbook

Control tasks according to the collection of tasks A.V. Peryshkin. Physics. 7 - 9 Option 1 Option 2 No. 1425, No. 1426, No. 1432 No. 1429 Solve 8. Complete control tasks

Thank you for your work!

Sources of information Printed materials 1. A.V. Peryshkin, E.M. Gutnik. Physics Grade 9, - M, Bustard, 2012 2. A.P. Rymkevich. Physics. Problem book 10 - 11 classes, Bustard, M. - 2012 Internet resources. 3. Picture. Question mark. http://ru.fotolia.com/id/51213056 4. Picture. Reading emoticon. http://photo.sibnet.ru/alb55017/ft1360515 / 5. Picture. Call from class. http://learning.9151394.ru/course/view.php?id=3603&topic=27 6. Picture. Ball and groove. http:// www.uchmarket.ru/d_13729.htm

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