A demonstration device for force synthesis and decomposition experiment

Abstract

The utility model discloses a demonstration device for force synthesis and decomposition experiment belongs to physical teaching aid technical field, including base, the top fixedly connected with support plate of base, the top of support plate is provided with protractor, the surface of protractor is connected with the rest table for placing weight, both sides of rest table bottom are all provided with telescopic link, the other end of telescopic link is provided with weighing sensor, the surface of weighing sensor is provided with the fixed structure for fixing weighing sensor angle, the surface of support plate is provided with adjusting hole, the surface of fixed structure and adjusting hole's inner chamber are slidably connected, adjusting hole is half round arc shape setting, adjusting hole sets up as 180 DEG, thereby avoids the deviation of reading, can accurate to the resultant force, component force and angle quantitative analysis, improves the teaching effect of teaching staff to student.

Description

Technical Field

[0001] This utility model relates to the technical field of physics teaching aids, specifically a demonstration device for experiments on the composition and decomposition of forces. Background Technology

[0002] According to announcement number CN206601864U, a force composition and decomposition apparatus includes a hollow force composition and decomposition plate. Two symmetrical arcs are formed on the force composition and decomposition plate. A horizontal beam, movable vertically along the center of the plate, is movably mounted. A protractor, movable horizontally, is mounted on the horizontal beam. A scale is provided on the force composition and decomposition plate to observe the distance the horizontal beam moves vertically. A plumb bob is also mounted on the force composition and decomposition plate. This force composition and decomposition apparatus is easy for students to operate and for teachers to demonstrate, enabling a comprehensive exploration of "force composition and decomposition," and verifying the dynamic equilibrium of three forces. It solves problems existing in this lesson, reduces experimental errors, and improves experimental accuracy.

[0003] The force composition and decomposition apparatus described above cannot directly observe the magnitude of the component forces, leading to reading deviations. It is also impossible to accurately and quantitatively analyze the resultant force, component forces, and angles, which affects the teaching effectiveness of instructors. Therefore, we need to propose a demonstration device for force composition and decomposition experiments. Utility Model Content

[0004] The purpose of this invention is to provide a demonstration device for the experiment of force composition and decomposition, thereby avoiding reading deviations and enabling precise quantitative analysis of resultant force, component force, and angle, thus improving the teaching effectiveness for students and solving the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a demonstration device for the experiment of force composition and decomposition, comprising a base, a support plate fixedly connected to the top of the base, a protractor provided at the top of the support plate, a platform for placing weights connected to the surface of the protractor, telescopic rods provided on both sides of the bottom end of the platform, a weighing sensor provided at the other end of the telescopic rods, a fixing structure for fixing the angle of the weighing sensor provided on the surface of the weighing sensor, an adjustment hole provided on the surface of the support plate, the surface of the fixing structure slidingly connected to the inner cavity of the adjustment hole, the adjustment hole being semi-circular in shape, and the adjustment hole being set to 180°.

[0006] Preferably, the outer wall of the support plate is provided with a groove, and the inner cavity of the groove of the support plate is provided with a scale.

[0007] Preferably, the upper surface of the base is further provided with a support structure, the support structure including a support column, the bottom end of the support column being fixedly connected to the upper surface of the base, the surface of the shelf having a rectangular hole, and the surface of the support column being slidably connected to the inner cavity of the rectangular hole.

[0008] Preferably, a slide rail is bolted to the top of the support plate, and a slide groove is provided on the outer side wall of the shelf. The surface of the slide rail is slidably connected to the inner cavity of the slide groove. Two sets of slide rails are provided, and the two sets of slide rails are symmetrically distributed on both sides of the support column.

[0009] Preferably, the fixing structure includes a threaded screw, one end of which is bonded to the surface of the load cell with hot melt adhesive, and the other end of which passes through the adjustment hole and is threaded with a locking nut. The outer surface of the threaded screw is slidably connected to the inner cavity of the adjustment hole.

[0010] Preferably, the top end of the telescopic rod is connected to the lower surface of the shelf via a butterfly buckle, and the bottom end of the telescopic rod is bonded and fixed to the upper surface of the weighing sensor via hot melt adhesive.

[0011] Preferably, a reinforcing plate is fixedly connected to the bottom end of the support plate, and the bottom end of the reinforcing plate is fixedly connected to the top end of the base. The reinforcing plate is trapezoidal in shape.

[0012] Compared with the prior art, the beneficial effects of this utility model are: This invention provides a demonstration device for experiments on the composition and decomposition of forces. Through the cooperation of a weighing sensor and a telescopic rod, weights are added to a platform, transferring the weight to the telescopic rod, which then transmits the force to the weighing sensor. The weighing sensor allows for effective observation of the weighing reading. The protractor allows for direct observation of the angle the telescopic rod moves on the support plate after being subjected to force, facilitating calculations. The fixed structure allows for the secure mounting of the weighing sensor to the support plate, simplifying operation and preventing reading errors. It enables precise quantitative analysis of resultant forces, component forces, and angles, improving the teaching effectiveness for students.

[0013] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained through the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a rear view structural schematic diagram of the present invention; Figure 3 This is a schematic diagram of the structure of this utility model after removing the telescopic rod; Figure 4 This is a schematic diagram of the structure of the disassembly support column and locking nut of the shelf of this utility model. Figure 5 This utility model explores the principle of the parallelogram rule. Figure 6 This utility model demonstrates the principle of the parallelogram rule. Figure 7 The theoretical value of the resultant force of this utility model The resultant force measured by calculating the resultant force from each component force. Comparison chart of results; Figure 8 The theoretical value of the resultant force of this utility model The theoretical value of the resultant force calculated from each component force The results are shown in the comparison chart.

[0015] In the diagram: 1. Base; 2. Support plate; 3. Protractor; 4. Display platform; 5. Telescopic rod; 6. Weighing sensor; 7. Fixing structure; 71. Long thread screw; 72. Locking nut; 8. Adjustment hole; 9. Support structure; 91. Support column; 92. Rectangular hole; 10. Slide rail; 11. Slide groove; 14. Reinforcing plate. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-8 This utility model provides a technical solution: a demonstration device for the synthesis and decomposition of forces, including a base 1, a support plate 2 fixedly connected to the top of the base 1, a protractor 3 set at the top of the support plate 2, a platform 4 for placing weights connected to the surface of the protractor 3, telescopic rods 5 set on both sides of the bottom of the platform 4, a weighing sensor set at the other end of the telescopic rod 5, a fixing structure 7 for fixing the angle of the weighing sensor set on the surface of the weighing sensor, an adjustment hole 8 opened on the surface of the support plate 2, the surface of the fixing structure 7 is slidably connected to the inner cavity of the adjustment hole 8, the adjustment hole 8 is set in a semi-circular arc shape, and the adjustment hole 8 is set to 180°; Specifically, when calculating the component force, the magnitude of the component force can be obtained by multiplying the reading on the weighing sensor by the local gravitational acceleration g, and then by the cosine of the angle between the component force and the vertical plane. When exploring the relationship between the magnitude of the resultant force and the component forces, weights need to be added or removed on stage 4, and the changes in the reading of the weighing sensor at the component force end need to be observed and recorded. This will give the relationship between the magnitude of the resultant force and the component forces when the angle is constant, thus avoiding reading deviations. It allows for precise quantitative analysis of the resultant force, component forces, and angles, improving the teaching effectiveness for students.

[0018] Furthermore, the outer wall of the support plate 2 is provided with a groove, and the inner cavity of the groove of the support plate 2 is provided with a scale. By observing the scale on the scale, the angle between the telescopic rods 5 on both sides and the platform 4 can be obtained.

[0019] Preferably, the upper surface of the base 1 is also provided with a support structure 9, which includes a support column 91. The bottom end of the support column 91 is fixedly connected to the upper surface of the base 1. A rectangular hole 92 is opened on the surface of the shelf 4. The surface of the support column 91 slides in the inner cavity of the rectangular hole 92. Through the cooperation between the support column 91 and the rectangular hole 92, the shelf 4 is supported, so that the shelf 4 can drive the protractor 3 to rise and fall on the surface of the support column 91. By adjusting the height of the shelf 4, the angle of the telescopic rods 5 on both sides of the bottom end of the shelf 4 can be adjusted.

[0020] In addition, a slide rail 10 is bolted to the top of the support plate 2, and a slide groove 11 is provided on the outer side wall of the platform 4. The surface of the slide rail 10 is slidably connected to the inner cavity of the slide groove 11. Two sets of slide rails 10 are provided, and the two sets of slide rails 10 are symmetrically distributed on both sides of the support column 91. The cooperation between the slide rail 10 and the slide groove 11 supports both sides of the platform 4, preventing the angle from shifting when the platform 4 is vertically raised and lowered, and improving the stability of the platform 4 when it moves.

[0021] In a further preferred embodiment, the fixing structure 7 includes a threaded screw 71. One end of the threaded screw 71 is bonded to the surface of the load cell with hot melt adhesive, and the other end of the threaded screw 71 passes through the adjustment hole 8 and is connected to a locking nut 72 by threads. The outer surface of the threaded screw 71 is slidably connected to the inner cavity of the adjustment hole 8. When the load cell transmits the force to the threaded screw 71, the threaded screw 71 slides in the adjustment hole 8, thereby adjusting the angle of the load cell on the support plate 2. When investigating the relationship between the magnitude of the resultant force and the component forces, the threaded screw 71 is locked by the locking nut 72. By simply adding weights to the platform 4 and observing and recording the changes in the reading of the load cell at the component force end, the relationship between the magnitude of the resultant force and the component forces can be obtained when the angle is constant.

[0022] Specifically, the top of the telescopic rod 5 is connected to the lower surface of the platform 4 via a butterfly buckle, and the bottom of the telescopic rod 5 is bonded and fixed to the upper surface of the weighing sensor 6 with hot melt adhesive. The telescopic rod 5 and the platform 4 are connected vertically, which can effectively transmit the component force to the weighing sensor along with the telescopic rod 5, reducing the influence of factors such as friction on the experimental results of the demonstration instrument.

[0023] Preferably, a reinforcing plate 14 is fixedly connected to the bottom end of the support plate 2. The bottom end of the reinforcing plate 14 is fixedly connected to the top end of the base 1. The reinforcing plate 14 is trapezoidal in shape. By setting the reinforcing plate 14, the other side of the support plate 2 is supported, thereby improving the stability of the support plate 2.

[0024] Experimental principle: When two forces are combined, a parallelogram is constructed with the line segments representing these two forces as adjacent sides. The diagonal between these two adjacent sides represents the magnitude and direction of the resultant force. This is called the parallelogram rule. The magnitude of the resultant force can be calculated from the mass of the weights placed on platform 4. By measuring the load cells at both load cells, the mass at each load cell can be determined. Substituting this mass into the local gravitational acceleration, the magnitude of the component force can be calculated. and ; Investigating the parallelogram law principle, such as Figure 5 As shown, the parallelogram rule is used to analyze the force process, as follows: Figure 6 As shown, component forces , The angles between them and their vertical plane and The sum of the products of the cosine values The force exerted by the four weights on the platform is equal to the force applied by the platform. .Right now ; ; — Magnitude of the force component at the left end (N); — Magnitude of the force component on the right end (N); ——Left end force component end The angle with the vertical plane; ——Right-end force component end The angle with the vertical plane; — Component force , The angles between them and their vertical plane and The sum of the products of the cosine values ​​(N).

[0025] Experimental method for investigating the relationship between the magnitude of the resultant force and the magnitude of the component forces under the condition of a fixed angle between the component forces: Keep the platform 4 and the protractor 3 horizontal. By moving the telescopic rod 5, you can observe the angle between the telescopic rod 5 and the vertical plane. That is, the position of the telescopic rod 5 on the protractor 3 is the angle between the force component end and the vertical plane.

[0026] When calculating the component force, simply multiply the reading on the weighing sensor by the local gravitational acceleration g, and then multiply by the cosine of the angle between the component force and the vertical plane to obtain the magnitude of the component force. To investigate the relationship between the magnitudes of the resultant force and the component forces, use a long threaded screw 71 to fix the angle of the component force end. Simply add weights to the platform 4, observe and record the changes in the weighing sensor reading at the component force end, and you can obtain the relationship between the magnitudes of the resultant force and the component forces when the angle is constant.

[0027] Example of experimental procedure: Taking a 45° angle between the force component and the vertical direction as an example: (1) Place the wooden block into the groove 11, put the long thread screw 71 into the hollow ring, and screw the locking nut 72 and washer on the end. Fix the two telescopic rods 5 to the same length of 20cm.

[0028] (2) Adjust one of the telescopic rods 5 to the position of 90° on the protractor 3, without applying pressure, to ensure that the resultant end platform 4 remains horizontal. Start the weighing sensor 6, measure the mass of the weighing sensor 6, the telescopic rod 5 and the connecting wooden block at this time, and record the data; then measure the mass of the weighing sensor 6, the telescopic rod 5 and the connecting wooden block in the same way, and record the initial value of the recording device.

[0029] (3) Place the two telescopic rods 5 at the protractor 3, 45° and 135° respectively, tighten the end of the long thread screw 71 and the locking nut 72 to fix the position of the telescopic rods 5 and ensure that the resultant end of the platform 4 remains horizontal.

[0030] (4) Start the weighing sensor 6, and place weights of different masses on the platform 4, observe the values ​​of the two component force end weighing sensors 6 and record the data.

[0031] (5) When calculating the magnitude of the component force, the value of the weighing sensor 6 is multiplied by the local gravitational acceleration, and then multiplied by the cosine of the angle between the component force and the vertical plane to get the magnitude of the component force.

[0032] Data recording and processing: Taking a 45° angle between the force component and the vertical direction as an example The data records for investigating the magnitudes of the resultant force and the component forces are shown in Table 1.

[0033] When the telescopic rod is at 90°, the initial reading at the left end is 0g; the initial reading at the right end is also 0g. The angle between the force component end and the vertical direction is 45°, and the gravitational acceleration g is taken as 10. .

[0034] Table 1. Data records on the magnitudes of the resultant force and component forces under the condition of a fixed angle between the component forces.

[0035] ; ; ; ; In the formula —The weight (N) of the weights placed on the platform 4; —The reading of the load cell 6 on the left force component end; —The reading of the load cell 6 at the right-hand force component end. The theoretical value of the resultant force was obtained from the above data analysis. The result of the calculated resultant force measured from each component force The comparison chart of the theoretical and measured values ​​of the resultant force is shown below. Figure 7 As shown, the left side represents the theoretical value, and the right side represents the measured value.

[0036] Based on the data analysis of the magnitudes of the resultant force and component forces under the condition of a fixed angle between the component forces, it can be concluded that when the angle between the component forces is fixed, the larger the resultant force, the larger the component forces. Furthermore, the calculated measured values ​​of the resultant force from each component force... Theoretical value The error between and is small, which can verify the parallelogram rule.

[0037] Experimental method for investigating the relationship between component forces and angles under the condition of a fixed resultant force: Keeping the platform 4 and protractor 3 horizontal, move the telescopic rod 5. The angle between the telescopic rod 5 and the vertical plane, i.e., the position of the telescopic rod 5 on the protractor 3, is the angle between the component force end and the vertical plane. To investigate the relationship between the resultant force, component forces, and angle, place the same number of weights on the platform 4. By adjusting different angles of the component force ends, observe and record the values ​​of the weighing sensors 6 on the left and right component force ends, calculate the component forces at the left and right ends, and use the parallelogram rule to calculate the resultant force of the two component forces in the vertical direction. This gives us the relationship between the resultant force, component forces, and angle, as well as the law of how the component forces change with the angle when the resultant force remains constant.

[0038] Example of experimental procedure: Taking an angle of 30° between the force component end and the vertical direction as an example: (1) With the two telescopic rods 5 of varying lengths, first place one telescopic rod 5 at the 90° position of the protractor 3 without applying pressure, ensuring that the telescopic rod 5 can smoothly pass through the 0° to 90° position of the slide groove 11, and keeping the platform 4 horizontal. Start the weighing sensor 6, measure the mass of the weighing sensor 6, the telescopic rod 5, and the connecting wooden block at this time, and record the data; then place the other telescopic rod 5 in the same way, measure the mass of the weighing sensor 6, the telescopic rod 5, and the connecting wooden block, and record the initial value of the device.

[0039] (2) Fix the position of the telescopic rod 5, place the weight on the platform 4, obtain and record the values ​​of the resultant and component forces at 90°, then loosen the fixing screw, place the two telescopic rods 5 at the 60° and 120° positions of the protractor 3 respectively, tighten the end of the long thread screw 71 and the locking nut 72, fix the position of the telescopic rod 5, and ensure that the platform 4 at the resultant force end remains horizontal.

[0040] (3) Using the same method as above, place the two telescopic rods 5 at the 30° and 150° positions of the protractor 3 respectively; place them at the 60° and 120° positions of the protractor 3 respectively; place them at the 40° and 140° positions of the protractor 3 respectively; place them at the 50° and 130° positions of the protractor 3 respectively; place them at the 70° and 110° positions of the protractor 3 respectively; tighten the locking nut 72 at the end of the long thread screw 71 to fix the position of the telescopic rods 5 and ensure that the resultant end platform 4 remains horizontal.

[0041] (4) On the platform 4 at the resultant force end, the weights placed there should be the same mass. Record the mass of the weights and calculate the magnitude of the resultant force. That is, keep the magnitude of the resultant force consistent. Observe the values ​​of the weighing sensors 6 at the two component force ends and record the data.

[0042] (5) When calculating the magnitude of the component force, the value of the weighing sensor 6 needs to be multiplied by the local gravitational acceleration, and then multiplied by the cosine of the angle between the component force end and the vertical plane to get the magnitude of the component force end.

[0043] Data recording and processing: Taking a 30° angle between the force component and the vertical direction as an example: The data on the relationship between the component forces and angles under the condition of a fixed resultant force are recorded in Table 2.

[0044] When the telescopic rod is at 90°, the initial reading at the left end is 0g, and the initial reading at the right end is also 0g. The gravitational acceleration g is taken as 10. .

[0045] Table 2. Data records of component forces and angles under the condition of a fixed resultant force.

[0046] ; ; ; ; The theoretical value of the resultant force was obtained from the above data analysis. The resultant force measured by calculating the resultant force from each component force. The result is shown in the comparison graph between the theoretical and measured values ​​of the resultant force. Figure 8 As shown, the left side represents the theoretical value, and the right side represents the measured value.

[0047] Based on the data analysis of the component forces and angles under the condition of a fixed resultant force, it can be concluded that when the magnitude of the resultant force is fixed, the component forces decrease as the angle increases, and the calculated resultant force values ​​of each component force are... Compared with theoretical value The error between and is small, and it can also verify the parallelogram rule.

[0048] The above data shows that when the angle between the component forces is fixed, the larger the resultant force, the larger the component forces. When the resultant force is fixed, the magnitude of the component forces decreases as the angle increases. In the teaching process, quantitative experiments can be conducted to explore the relationship between the resultant force, component forces, and angle, facilitating student understanding and giving them a perceptual understanding of the concept that force is a vector. From the two experiments above, it can be concluded that the direction of the resultant force is always vertically downward, while the direction of the component forces changes with the movement of the telescopic rod 5, always along the opposite direction of the telescopic rod 5. Furthermore, the magnitude of the resultant force can be calculated using the parallelogram rule. This demonstrator can fix the angle using the threaded screw 71 and the locking nut 72, or place a certain number of weights on the platform 4 to control the magnitude of the resultant force, causing corresponding changes in the readings at the component force end. This allows for the exploration of the composition law of two forces at an angle to each other. Alternatively, by keeping the weights of equal mass and adjusting the angles at the component force end, the relationship between the component forces and angles under a fixed resultant force can be explored, thereby verifying the parallelogram law. This helps enhance teaching effectiveness, avoids reading deviations, and allows for precise quantitative analysis of resultant force, component forces, and angles, improving the teaching effectiveness for students.

[0049] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A demonstration device for the experiment of force composition and decomposition, characterized in that, include: The base (1) has a support plate (2) fixedly connected to its top end. The support plate (2) has a protractor (3) at its top end. The surface of the protractor (3) is connected to a platform (4) for placing weights. Telescopic rods (5) are provided on both sides of the bottom of the platform (4), and a weighing sensor (6) is provided at the other end of the telescopic rod (5). A fixing structure (7) for fixing the angle of the weighing sensor (6) is provided on the surface of the weighing sensor (6). The surface of the support plate (2) is provided with an adjustment hole (8), the surface of the fixing structure (7) is slidably connected to the inner cavity of the adjustment hole (8), the adjustment hole (8) is set in a semi-circular arc shape, and the adjustment hole (8) is set to 180°.

2. The experimental demonstration device for the composition and decomposition of forces according to claim 1, characterized in that: The outer wall of the support plate (2) is provided with a groove, and the inner cavity of the groove of the support plate (2) is provided with a scale.

3. The experimental demonstration device for the composition and decomposition of forces according to claim 1, characterized in that: The upper surface of the base (1) is also provided with a support structure (9), the support structure (9) includes a support column (91), the bottom end of the support column (91) is fixedly connected to the upper surface of the base (1), and a rectangular hole (92) is opened on the surface of the shelf (4), and the surface of the support column (91) is slidably connected to the inner cavity of the rectangular hole (92).

4. The experimental demonstration device for the composition and decomposition of forces according to claim 3, characterized in that: The top of the support plate (2) is bolted with a slide rail (10), and the outer wall of the platform (4) is provided with a slide groove (11). The surface of the slide rail (10) is slidably connected to the inner cavity of the slide groove (11). There are two sets of slide rails (10), and the two sets of slide rails (10) are symmetrically distributed on both sides of the support column (91).

5. The experimental demonstration device for the composition and decomposition of forces according to claim 1, characterized in that: The fixing structure (7) includes a threaded screw (71). One end of the threaded screw (71) is bonded to the surface of the weighing sensor (6) by hot melt adhesive. The other end of the threaded screw (71) passes through the adjustment hole (8) and is threaded with a locking nut (72). The outer surface of the threaded screw (71) is slidably connected to the inner cavity of the adjustment hole (8).

6. The experimental demonstration device for the composition and decomposition of forces according to claim 1, characterized in that: The top end of the telescopic rod (5) is connected to the lower surface of the shelf (4) by a butterfly buckle, and the bottom end of the telescopic rod (5) is bonded and fixed to the upper surface of the weighing sensor (6) by hot melt adhesive.

7. The experimental demonstration device for the composition and decomposition of forces according to claim 1, characterized in that: The bottom end of the support plate (2) is fixedly connected to a reinforcing plate (14), and the bottom end of the reinforcing plate (14) is fixedly connected to the top end of the base (1).

8. The experimental demonstration device for the composition and decomposition of forces according to claim 7, characterized in that: The reinforcing plate (14) is trapezoidal in shape.

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