"Scientific Exploration: Elastic Force" Interaction PPT (Exploring the relationship between the elastic force and elongation of the spring in the second lesson)

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"Scientific Exploration: Elastic Force" Interaction PPT (Exploring the relationship between the elastic force and elongation of the spring in the second lesson)

Part One: Clarify the Principles

1. Experimental purpose

1. Explore the relationship between spring force and elongation.

2. Understand the working principle of spring dynamometer.

2. Experimental equipment

Iron stand, spring, millimeter scale, some hook codes, and graph paper.

3. Experimental Principle and Design

1. As shown in Figure 1, when the hook code is hung at the lower end of the spring, the spring will stretch. According to the knowledge of two-force balance, the elastic force generated by the spring during balance is equal to the gravity of the hooked code.

2. The elastic force of the spring can be changed by changing the number of hanging hook codes. The length of the spring can be measured directly with a scale. The elongation can be calculated by subtracting the original length of the spring from the stretched length.

4. Experimental steps

1. Install the experimental device, as shown in Figure 2, and note the scale l0 corresponding to the lower end of the spring when the code is not hooked.

2. Hang a hook code at the lower end of the spring. When balancing, note the total length l1 of the spring and the mass m1 of the hook code.

3. Increase the number of hook codes, repeat step 2, and calculate the elongation x and spring force F of the spring each time, and fill in the data in the table.

5. Data analysis

1. Take the elastic force F (the magnitude is equal to the gravity of the hooked code) as the ordinate, and take the extension x of the spring as the abscissa, use the point tracing method to draw the graph. Connect all the points to get a graph of the elastic force F changing with the spring extension x, as shown in Figure 3.

2. Using the spring elongation as the independent variable, write the functional relationship between the elastic force and the spring elongation. The constant in the function expression is the stiffness coefficient of the spring. This constant can also be solved based on the slope of the F-x graph. k=ΔFΔx.

6. Precautions

1. The hook should not be too heavy to prevent the spring from being overstretched beyond its elastic limit.

2. The quality difference of the hooked codes should be as large as possible each time, so that the points drawn on the coordinates are as sparse as possible, so that the graph produced in this way is accurate.

3. When measuring the length of a spring, it must be measured when the spring is hanging vertically and in a balanced state. The scale must be kept vertical and close to the spring to avoid increasing the error.

4. When tracing points and lines, the points drawn may not all fall on a straight line, but attention should be paid to making the points evenly distributed on both sides of the straight line.

5. When recording data, pay attention to the corresponding relationship and units of elastic force and spring elongation.

7. Error analysis

Since the measurement of the original length and extension of the spring is inconvenient to operate, there is a large measurement error. In addition, due to the influence of the spring's own gravity, that is, when no weight is placed, the spring already has a The amount of elongation, so the drawing line often does not pass the origin.

Scientific exploration of elasticity PPT, part 2: interpretation of typical examples

Experimental principles and operations

As shown in Figure A, use an iron stand, a spring, and multiple hooks with known and equal masses to explore the relationship between the elastic force of the spring and the elongation of the spring within the elastic limit.

(1) In order to complete the experiment, the experimental equipment needed is: ________.

(2) The physical quantities that need to be measured in the experiment are: ____________________________________________.

(3) Figure B is the F-x graph of spring force F and spring elongation x. From this, the stiffness coefficient of the spring can be calculated as ________ N/m. The reason why the graph does not reach the origin is ____________________.

(4) In order to complete this experiment, the experimental steps designed are as follows:

A. Taking the spring elongation as the abscissa and the elastic force as the ordinate, draw the points corresponding to each group (x, F) and connect them with smooth curves;

B． Note down the mark l0 on the scale at the lower end of the spring when it is not hooked;

C. Fix the iron stand on the table, tie one end of the spring to the beam, and fix a scale vertically near the spring;

Experimental data processing and error analysis

(2019•The end of the first semester of high school in Chuzhou, Anhui) An experimental group conducted an experiment to "explore the relationship between elastic force and spring elongation." During the experiment, first place the spring flat on the table, and use a ruler to measure the original length of the spring L0 = 4.6 cm, then hang the spring vertically, hook the code at the lower end, record the corresponding spring length L for each additional hook code, the data record is as shown in the following table:

(1) Draw an F-L graph on the graph based on the data in the table;

(2) From this graph, it can be obtained that the spring stiffness coefficient k = ________N/m;

(3) The reason why the intersection coordinate of the graph line and the L axis is greater than L0 is ____________________________.

Experimental improvement and innovation

(2019·Final of the first grade of Sichuan Tanghu Middle School) Use the device as shown in the figure to measure the stiffness coefficient of the spring. One end of the spring to be measured is fixed at point A, and the other end is wrapped with a thin wire around the fixed pulley hook code, with a vertical Centimeter scale placed straight. When two hook codes are hung, the scale line corresponding to a certain point P on the line is shown by the dotted line ab in the figure. When three hook codes are hung, the scale line corresponding to a certain point P on the line is shown by the dotted line cd in the figure. Show. It is known that the mass of each hook code is 50 g, and the gravity acceleration g=9.8 m/s2. The scale reading at the dotted line ab is d1=______m; then the stiffness coefficient of the tested spring is ________N/m.

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Update Time: 2024-06-23

This template belongs to Physics courseware Lu Ke Edition High School Physics Compulsory Course One industry PPT template

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