Angular momentum demonstration instrument

Abstract

The utility model discloses an angular momentum demonstration instrument which is used for demonstrating angular momentum conservation and angular momentum precession, the angular momentum demonstration instrument used for demonstrating angular momentum conservation comprises a base, a rotating table, a power supply device, a plurality of support arms, a plurality of electromagnets and a plurality of metal balancing weights, the rotating table is rotatably installed on the base; the power supply device is arranged in a space between the base and the rotating table; one ends of the multiple supporting arms are fixed to the rotating table at intervals in the circumferential direction, and the other ends of the multiple supporting arms are tail ends which are obliquely arranged upwards. The electromagnets are mounted at the tail ends of the corresponding support arms; the plurality of electromagnets are electrically connected with the power supply device; the metal balancing weights are arranged on the corresponding supporting arms in a sleeving mode, and the metal balancing weights are arranged after the electromagnets are powered on. The angular momentum demonstration instrument can vividly demonstrate laws related to angular momentum, and is beneficial to science popularization of basic principles of angular momentum to the public.

Description

Technical Field

[0001] The utility model relates to an angular momentum demonstration instrument, belonging to the technical field of science education equipment. Background Technique

[0002] At present, the law of conservation of angular momentum when a rigid body rotates around a fixed axis: For a rigid body rotating around a fixed axis, if the resultant torque of the external forces acting on the axis of rotation is zero, then the angular momentum of the rigid body about this axis does not change with time and remains a constant value.

[0003] At present, the concept of angular momentum is generally learned in courses related to rigid body mechanics such as "University Physics" and "Theoretical Mechanics" in colleges and universities. It is a key point and also a difficult point in mechanics. In teaching, using the traditional lecture method, students often find it difficult to understand or master its physical essence within just a few class hours. To deepen students' understanding of knowledge and laws related to angular momentum and arouse students' interest in learning and exploration desire, the angular momentum demonstrator has gradually become a commonly used classroom teaching auxiliary instrument.

[0004] At present, there are various angular momentum demonstration devices in domestic colleges and universities. For example, the Zhukovsky chair requires a person to sit on the chair to become part of the experimental device when demonstrating the conservation of angular momentum. It has certain requirements for the physical fitness of the experimenter, and the device is large in size and inconvenient to carry; the three-ball type angular momentum conservation demonstrator, the ball-swinging type angular momentum conservation demonstrator, and the handheld torque mutation angular momentum conservation demonstrator. Although the above demonstrators are small in size and simple in structure, they can only demonstrate the angular momentum conservation theorem.

[0005] On the other hand, precession is also a physical phenomenon closely related to the angular momentum of a rigid body. Specifically, when a rotating rigid body is subjected to an external torque, its axis of rotation will rotate around a certain center. This phenomenon is also called nutation. Precession involves the rotation of an object around a certain axis of rotation while the axis of rotation rotates around another axis. During precession, the rotation direction of the object can be the same as or different from its rotation direction. For example, a gyroscope will rotate around an axis as the center while maintaining its own rotation state when subjected to an external torque. Precession is not limited to gyroscopes and can also be applied to other rotating objects. For example, the conical motion of the Earth's axis of rotation around the yellow axis also reflects the concept of precession. Ω = M / Jω where: Ω represents the precession angular velocity, M represents the applied torque, J represents the moment of inertia of the object, and ω represents the angular velocity of the object. This formula shows that when an object is subjected to a torque, its precession angular velocity is proportional to the applied torque and the moment of inertia of the object, and inversely proportional to the angular velocity of the object.

[0006] After a search of the prior art, it is found that a Chinese patent with the publication number CN110930831A discloses an angular momentum conservation demonstrator based on a Hoberman sphere. This patent uses a Hoberman sphere to demonstrate angular momentum conservation, which is large in volume and inconvenient to carry, and is not suitable for use in college courses. Summary of the Invention

[0007] The technical problem to be solved by the present utility model is to overcome the defects of the prior art and provide an angular momentum demonstrator that can vividly demonstrate the laws related to angular momentum and help popularize the basic principles of angular momentum to the public.

[0008] To solve the above technical problem, the technical solution of the present utility model is: an angular momentum demonstrator for demonstrating angular momentum conservation, comprising:

[0009] A base;

[0010] A rotating table, which is rotatably mounted on the base;

[0011] A power supply device, which is arranged in the space between the base and the rotating table;

[0012] A plurality of support arms, one ends of the plurality of support arms are fixedly arranged at intervals along the circumferential direction on the rotating table, and the other ends are the ends, and the ends are inclined upward;

[0013] A plurality of electromagnets, which are mounted on the ends of the corresponding support arms;

[0014] The plurality of electromagnets are all electrically connected to the power supply device;

[0015] A plurality of metal counterweights, the metal counterweights are sleeved on the corresponding support arms, and the metal counterweights are adapted to be adsorbed by the electromagnets on the corresponding support arms after the electromagnets are energized.

[0016] Further, in order to facilitate the adjustment of the metal counterweights, the metal counterweights include:

[0017] A metal hanging ring, which is detachably sleeved on the support arm, and the metal hanging ring is adapted to be adsorbed by the electromagnet;

[0018] A hanging chain, one end of the hanging chain is connected to the metal hanging ring;

[0019] A heavy object, which is detachably connected to the other end of the hanging chain.

[0020] The present utility model also provides an angular momentum demonstrator for demonstrating angular momentum precession, comprising:

[0021] A base;

[0022] A rotating table, which is rotatably mounted on the base;

[0023] A power supply device, which is arranged in the space between the base and the rotating table;

[0024] An arm, one end of which is fixed on the rotating table;

[0025] A rotary drive member, which is mounted on the other end of the arm;

[0026] The rotary drive member is electrically connected to the power supply device;

[0027] A rotary counterweight, which is mounted on the driving end of the rotary drive member, and the rotary plane of the rotary counterweight is perpendicular to the rotary plane of the rotating table.

[0028] Furthermore, a specific type of power supply device is provided. The power supply device is an internal power supply, and the internal power supply includes a battery and a power supply board mounted on the rotating table;

[0029] The power supply board is provided with an input end and an output end;

[0030] The battery is adapted to be electrically connected to the input end of the power supply board through a wire;

[0031] The output end of the power supply board is adapted to be electrically connected to the rotary drive member or a plurality of the electromagnets through a wire.

[0032] Furthermore, a specific type of power supply device is provided. The power supply device is an external power supply, and the external power supply includes a power supply board, a slip ring and a power cord;

[0033] The power supply board is mounted in the base, and the power supply board is provided with an input end and an output end;

[0034] One end of the power cord is electrically connected to the input end of the power supply board, and the other end extends out of the base;

[0035] The slip ring is provided with a fixed seat and a rotating end, wherein the fixed seat is fixed on the base, and the rotating end is connected to the rotating table and rotates synchronously with the rotating table;

[0036] The fixed seat and the rotating end are provided with connecting wires that are connected;

[0037] The output end of the power supply board is adapted to be electrically connected to the rotary drive member or a plurality of the electromagnets through the connecting wire of the slip ring.

[0038] Further, for the convenience of control, the angular momentum demonstration instrument further includes a switch, which is installed on the base or the rotating table, and the switch is electrically connected to the power supply device through a wire;

[0039] The switch is adapted to control the power supply device to be powered on and off.

[0040] Further, for the convenience of threading wires, a wire hole is provided inside the support arm.

[0041] Further, the angular momentum demonstration instrument further includes a controller, which is electrically connected to the power supply device and the rotation driving member respectively;

[0042] A timer is provided inside the controller;

[0043] The timer is adapted to start timing operation after a set timing;

[0044] The controller is adapted to control the rotation driving member to rotate in the reverse direction through the power supply device after the timing of the timer ends.

[0045] By adopting the above technical solutions, the present utility model has the following beneficial effects:

[0046] In the present utility model, first, manually drive the rotating table to rotate relative to the base, and then the power supply device is powered on to activate the electromagnet to adsorb the metal counterweight at the high point of the distal end of the support arm. When the power supply of the power supply device is disconnected, the metal counterweight begins to slide down along the support arm. Due to the action of the law of conservation of angular momentum, the rotation speed of the rotating table and the support arm and the metal counterweight thereon gradually increases. This process not only vividly demonstrates the physical phenomenon of conservation of angular momentum to the public, but also intuitively shows the influence of the change of moment of inertia on the rotation speed, enhancing its educational and popular science effects.

[0047] In addition, by using the rotation driving member and the rotation counterweight, when the rotation driving member is powered on, the rotation counterweight on the support arm first rotates clockwise, driving the rotating table to rotate clockwise; then when the rotation counterweight rotates counterclockwise, the rotating table also follows to rotate counterclockwise, thus vividly demonstrating the principle of angular momentum precession.

[0048] In summary, the present utility model provides an intuitive and flexible demonstration method. This not only helps to improve the public's understanding and interest in the basic principles of angular momentum, but also provides an efficient and practical tool for physics teaching and scientific research. Description of the Drawings

[0049] Figure 1 It is a three-dimensional structural schematic diagram of the angular momentum demonstration instrument in Embodiment 1 of the present utility model;

[0050] Figure 2Schematic cross-sectional structure diagram of the angular momentum demonstration instrument in Embodiment 1 of the present utility model;

[0051] Figure 3 Schematic three-dimensional structure diagram of the angular momentum demonstration instrument in Embodiment 2 of the present utility model;

[0052] Figure 4 Schematic cross-sectional structure diagram of the angular momentum demonstration instrument in Embodiment 2 of the present utility model. Detailed implementation manners

[0053] In order to make the content of the present utility model easier to be clearly understood, the present utility model will be further described in detail below according to specific embodiments in conjunction with the accompanying drawings.

[0054] Embodiment 1: As Figures 1-4 shown, this embodiment provides an angular momentum demonstration instrument for demonstrating the conservation of angular momentum, including:

[0055] Base 1;

[0056] Rotating table 2, the rotating table 2 is rotatably installed on the base 1;

[0057] Power supply device, the power supply device is arranged in the space between the base 1 and the rotating table 2;

[0058] Six support arms 4, one ends of the six support arms 4 are circumferentially and spacedly fixed on the rotating table 2, and the other ends are the ends, and the ends are inclined upward;

[0059] Six electromagnets 5, the electromagnets 5 are installed on the ends of the corresponding support arms 4;

[0060] The six electromagnets 5 are all electrically connected to the power supply device;

[0061] Six metal counterweights, the metal counterweights are sleeved on the corresponding support arms 4, and the metal counterweights are adapted to be adsorbed by the electromagnets 5 on the corresponding support arms 4 after the electromagnets 5 are powered on.

[0062] In this embodiment, as Figure 1 shown, first manually drive the rotating table 2 to rotate relative to the base 1, and then the power supply device is powered on to activate the electromagnet 5 to adsorb the metal counterweight at the high point of the distal end of the support arm 4. When the power supply of the power supply device is disconnected, the metal counterweight begins to slide down along the support arm 4. Due to the action of the law of conservation of angular momentum, the rotation speed of the rotating table 2 and the support arms 4 and the metal counterweights thereon gradually increases. This process not only vividly demonstrates the physical phenomenon of the conservation of angular momentum to the public, but also intuitively shows the influence of the change of the moment of inertia on the rotation speed, enhancing its educational and popular science effects.

[0063] The base 1 can be made of metal, and in some embodiments, it can also be an acrylic board. The number of the support arms 4, the electromagnets 5, and the metal counterweights is not limited to six and can be set according to specific requirements.

[0064] Specifically, as Figure 1 shown, the metal counterweight includes:

[0065] A metal hanging ring 61, which is detachably sleeved on the support arm 4 and is adapted to be adsorbed by the electromagnet 5;

[0066] A hanging chain 62, one end of which is connected to the metal hanging ring 61;

[0067] A heavy object 63, which is detachably connected to the other end of the hanging chain 62.

[0068] In this embodiment, as Figure 1 shown, through the design of the metal hanging ring 61, the hanging chain 62, and the heavy object 63, the metal counterweight can be flexibly assembled and disassembled. During use, first slide the metal hanging ring 61 onto the end of the support arm 4, then connect one end of the hanging chain 62 to the metal hanging ring 61, and finally connect the heavy object 63 to the other end of the hanging chain 62. In this way, a complete rotatable counterweight system is formed.

[0069] When the power supply device is turned on and powered to the electromagnet 5, the metal hanging ring 61 will be adsorbed by the electromagnet 5 at the end of the support arm 4, and the entire counterweight system will rotate with the rotating table 2. After power-off, the electromagnet 5 loses its suction force, and the metal hanging ring 61 will slide down along the inclined support arm 4. Since the moment of inertia of the entire counterweight system becomes smaller, according to the law of conservation of angular momentum, its rotational angular velocity will increase.

[0070] The larger the mass of the heavy object 63, the larger the moment of inertia of the entire counterweight system, and the more obvious the change in angular velocity. By adjusting the mass of the heavy object 63, the dynamic characteristics of the system can be conveniently changed to create different demonstration effects.

[0071] In addition, the heavy object 63 can also be in the shape of a plush toy or the like, making the change process of angular momentum more vivid and conducive to observers' understanding and memory.

[0072] Embodiment 2: As Figure 3 shown, this embodiment provides an angular momentum demonstration instrument for demonstrating angular momentum precession, including:

[0073] A base 1;

[0074] A rotating table 2, which is rotatably mounted on the base 1;

[0075] A power supply device, which is arranged in the space between the base 1 and the rotating table 2;

[0076] The support arm 4, one end of the support arm 4 is fixed on the rotating table 2;

[0077] The rotation driving member, the rotation driving member is installed at the other end of the support arm 4;

[0078] The rotation driving member is electrically connected to the power supply device;

[0079] The rotation counterweight 7, the rotation counterweight 7 is installed on the driving end of the rotation driving member, and the rotation plane of the rotation counterweight 7 is perpendicular to the rotation plane of the rotating table 2.

[0080] In this embodiment, as Figure 3 shown, by using the rotation driving member and the rotation counterweight 7, when the rotation driving member is powered on, the rotation counterweight 7 on the support arm 4 first rotates clockwise, driving the rotating table 2 to rotate clockwise; subsequently, when the rotation counterweight 7 rotates counterclockwise, the rotating table 2 also rotates counterclockwise, thus vividly demonstrating the principle of angular momentum precession.

[0081] Specifically, the angular momentum demonstration instrument further includes a controller, and the controller is electrically connected to the power supply device and the rotation driving member respectively;

[0082] A timer is provided inside the controller;

[0083] The timer is adapted to start timing operation after setting a timing;

[0084] The controller is adapted to control the rotation driving member to rotate in the reverse direction through the power supply device after the timer ends timing.

[0085] In this embodiment, in order to achieve an automated dynamic demonstration effect, a controller is added in this embodiment. The controller can be a simple timing circuit or a more complex programmable control unit, such as a single-chip microcomputer or a microcontroller.

[0086] The controller is connected to the power supply device and the rotation driving member respectively through wires. It integrates a timer circuit inside and can start timing according to a preset time value.

[0087] At the beginning of the demonstration, the operator first sets the timing duration on the controller, and then the controller starts the timer to start timing. At the same time, the controller powers on the rotation driving member through the power supply device, making it start to rotate in an initial direction, such as clockwise.

[0088] When the timer ends timing, the controller detects this state, and then controls the rotation direction of the rotation driving member to reverse through the power supply device, changing to the counterclockwise direction.

[0089] Through this automatic timed reversal method, the phenomenon that the rotation direction of the demonstration instrument changes when the rotating counterweight rotates forward and backward can be cyclically demonstrated, vividly showing the precession law.

[0090] Embodiment 3: This embodiment is basically the same as Embodiment 1, except that: specifically, as Figure 4 shown, the power supply device is an internal power supply, and the internal power supply includes a battery and a power supply board 311 installed on the rotating table 2;

[0091] The power supply board 311 is provided with an input end and an output end;

[0092] The battery is adapted to be electrically connected to the input end of the power supply board 311 through a wire;

[0093] The output end of the power supply board 311 is adapted to be electrically connected to the rotation driving member or the six electromagnets 5 through a wire.

[0094] In this embodiment, as Figures 1-2 shown, the design of using an internal power supply makes the entire angular momentum demonstration instrument easy to move and demonstrate on-site. The battery and the power supply board 311 are integrally installed on the rotating table 2 and can rotate together with the rotating table 2.

[0095] The battery provides power for the power supply board 311 and is connected to the input end of the power supply board 311 through a wire. The power supply board 311 integrates a circuit, which can regulate the voltage of the battery to a suitable level by step-down or step-up, and then output it from the output end to the rotation driving member or the electromagnet 5.

[0096] When in use, just correctly connect the battery to the input end of the power supply board 311 and turn on the switch on the power supply board 311 to start. If it is to drive the rotation driving member, the output end of the power supply board 311 needs to be connected to the rotation driving member through a wire; if it is to drive the electromagnet 5, the wire needs to be distributed to each electromagnet 5.

[0097] Adopting this internal power supply design, there is no need to prepare an external power supply separately, and the operation is more convenient. However, the battery life is limited, and it needs to be replaced or charged in time for long-term use.

[0098] In addition, a charging circuit can be integrated on the power supply board 311 so that it can charge the battery through an external charging line when the instrument is stationary, extending the use time.

[0099] Embodiment 4: This embodiment is basically the same as Embodiment 2, except that the power supply device is the internal power supply described in Embodiment 3.

[0100] Embodiment 5: As Figure 2As shown, this embodiment is basically the same as Embodiment 1, except that, specifically, the power supply device is an external power supply, and the external power supply includes a power supply board 311, an electric slip ring 321, and a power cord 331;

[0101] The power supply board 311 is installed inside the base, and an input end and an output end are provided on the power supply board 311;

[0102] One end of the power cord 331 is electrically connected to the input end of the power supply board 311, and the other end extends out of the base 1;

[0103] The electric slip ring 321 is provided with a fixed seat and a rotating end, wherein the fixed seat is fixed on the base 1, and the rotating end is connected to the rotating table 2 and rotates synchronously with the rotating table 2;

[0104] Connected wires are provided on the fixed seat and the rotating end;

[0105] The output end of the power supply board 311 is adapted to be electrically connected to the rotation driving member or the six electromagnets 5 through the connecting wire of the electric slip ring 321.

[0106] In this embodiment, as Figures 1-2 shown, with the design of an external power supply, the entire power supply device is separated from the rotating part, and the power supply is more stable and reliable. The power supply board 311 is fixedly installed inside the base 1, and is connected to an external power supply, such as the mains or a large-capacity battery pack, through the power cord 331 to obtain energy.

[0107] In order to achieve a non-tangled connection between the power supply board 311 and the rotating components, the electric slip ring 321 is selected. It consists of a fixed seat and a rotating end. The fixed seat is fixed on the base 1, and the rotating end is connected to the rotating table 2 and rotates together. There are built-in metal annular sliding contacts on the fixed seat and the rotating end, and the contacts are connected by flexible wires, thus forming a rotatable but non-tangled circuit.

[0108] When the rotating table 2 rotates, the rotating end of the electric slip ring 321 rotates accordingly, but the wires between it and the fixed seat will not get tangled. The output end of the power supply board 311 is connected to the connecting wire of the electric slip ring 321 through the wire passing through the fixed seat, and can stably supply power to the rotating components, the rotation driving member or the electromagnet 5.

[0109] The advantage of using an external power supply is that the power supply is stable and long-lasting, and there is no need to replace the built-in battery.

[0110] In addition, the external power supply can also select an adjustable-voltage linear DC power supply or a switching power supply. By adjusting the output voltage, the rotation speed of the rotation driving member or the magnetic force of the electromagnet 5 can be controlled, thereby adjusting the motion state of the entire demonstration system.

[0111] Embodiment 6: As Figures 1-4As shown, this embodiment is basically the same as Embodiment 3 or Embodiment 4, the difference being that: the angular momentum demonstration instrument further includes a switch 8, the switch 8 is installed on the base 1, and the switch 8 is electrically connected to the power supply device through a wire;

[0112] The switch 8 is adapted to control the power on and off of the power supply device.

[0113] In this embodiment, as Figures 1-2 shown, in order to facilitate the control of the start and stop of the entire angular momentum demonstration instrument, a switch 8 is installed outside the base 1. The switch 8 is electrically connected to the power supply line of the power supply device through a wire.

[0114] The switch 8 can be the most common mechanical switch, or a push-button switch or a toggle switch, etc. The user only needs to manually operate the position of the switch 8 to cut off or restore the path of the power supply line, thereby controlling the working state of the power supply device.

[0115] When the switch 8 is in the closed position, the entire power line is disconnected, and the battery or external power supply cannot provide electrical energy to the power supply board. The rotation drive member and the electromagnet 5 are both in a stationary state without power.

[0116] When the switch 8 is switched to the on position, the power line is connected, the power supply board obtains power and starts to work, supplying power to the rotation drive member or the electromagnet 5, and making the entire instrument enter the operating state.

[0117] By setting the switch 8, the operator can conveniently switch the instrument power supply to the standby state before the demonstration, and can also start or stop the instrument at any time when needed, avoiding the inconvenient operation of directly disconnecting the battery or external power supply.

[0118] Embodiment 7: This embodiment is basically the same as Embodiment 5 or Embodiment 6, the difference being that the switch 8 is installed on the rotating table 2.

[0119] Specifically, as Figures 1-2 shown, a wire hole is provided inside the support arm 4.

[0120] In this embodiment, as Figures 1-2 shown, in order to connect the wires neatly and orderly to the electromagnet 5 or the rotation drive member at the end of the support arm 4, the inside of the support arm 4 is designed to be hollow, and a wire hole is reserved.

[0121] By adopting the design of the built-in wire hole, the power cord and the wires can be completely hidden inside the support arm 4, making the appearance of the entire instrument more concise and beautiful, and the wires will not be tripped or broken by other moving parts.

[0122] In the specific embodiments described above, the technical problems solved, technical solutions and beneficial effects of the present utility model have been further described in detail. It should be understood that the above are only specific embodiments of the present utility model and are not used to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. An angular momentum demonstration instrument for demonstrating conservation of angular momentum, characterized in that: include: Base (1); A rotating platform (2), the rotating platform (2) being rotatably mounted on the base (1); A power supply device, the power supply device being arranged in the space between the base (1) and the rotating platform (2); A plurality of supporting arms (4), one end of each of the supporting arms (4) being fixed on the rotating platform (2) at intervals along the circumferential direction, and the other end being a terminal end, and the terminal end being arranged to tilt upward; A plurality of electromagnets (5), wherein the electromagnets (5) are mounted on the ends of the corresponding supporting arms (4); The plurality of electromagnets (5) are all electrically connected to the power supply device; A plurality of metal counterweight blocks are sleeved on the corresponding support arms (4); the metal counterweight blocks are adapted to be adsorbed by the electromagnet (5) on the corresponding support arms (4) after the electromagnet (5) is energized.

2. The angular momentum demonstration instrument according to claim 1, characterized in that: The metal counterweight comprises: a metal hanging ring (61), the metal hanging ring (61) being detachably mounted on the support arm (4), the metal hanging ring (61) being suitable for being adsorbed by the electromagnet (5); A hanging chain (62), one end of the hanging chain (62) being connected to the metal hanging ring (61); A weight (63), wherein the weight (63) is detachably connected to the other end of the hanging chain (62).

3. An angular momentum demonstration instrument for demonstrating angular momentum precession, characterized in that: include: Base (1); A rotating platform (2), the rotating platform (2) being rotatably mounted on the base (1); A power supply device, the power supply device being arranged in the space between the base (1) and the rotating platform (2); A support arm (4), one end of the support arm (4) being fixed on the rotating platform (2); A rotary drive member, the rotary drive member being mounted on the other end of the support arm (4); The rotary drive member is electrically connected to the power supply device; A rotating counterweight (7), wherein the rotating counterweight (7) is mounted on the driving end of the rotating drive member, and the rotating plane of the rotating counterweight (7) is perpendicular to the rotating plane of the rotating platform (2).

4. The angular momentum demonstration instrument according to claim 3, characterized in that: The power supply device is a built-in power supply, and the built-in power supply comprises a battery and a power supply board (311) mounted on the rotating platform (2); The power supply board (311) is provided with an input end and an output end; The battery is suitable for being electrically connected to the input terminal of the power supply board (311) via a wire; The output end of the power supply board (311) is suitable for being electrically connected to the rotary drive member via a wire.

5. The angular momentum demonstration instrument according to claim 3, characterized in that: The power supply device is an external power supply, and the external power supply comprises a power supply board (311), an electric slip ring (321) and a power line (331); The power supply board (311) is installed in the base, and the power supply board (311) is provided with an input end and an output end; One end of the power line (331) is electrically connected to the input end of the power supply board (311), and the other end extends out of the base (1); The electric slip ring (321) is provided with a fixed seat and a rotating end, wherein the fixed seat is fixed on the base (1), and the rotating end is connected to the rotating table (2) and rotates synchronously with the rotating table (2); The fixing seat and the rotating end are provided with connecting wires in communication; The output end of the power supply board (311) is suitable for being electrically connected to the rotating drive component via a connecting wire of the electric slip ring (321).

6. The angular momentum demonstration instrument according to claim 1 or 3, characterized in that: It also includes a switch (8), the switch (8) being mounted on the base (1) or the rotating platform (2), and the switch (8) being electrically connected to the power supply device via a wire; The switch (8) is suitable for controlling the power supply device to be powered on or off.

7. The angular momentum demonstration instrument according to claim 1 or 3, characterized in that: A wire hole is provided in the support arm (4).

8. The angular momentum demonstration instrument according to claim 3, characterized in that: It also includes a controller, which is electrically connected to the power supply device and the rotating drive member respectively; A timer is provided in the controller; The timer is suitable for starting the timing operation after setting the timing; The controller is suitable for controlling the rotary drive member to rotate in the reverse direction through the power supply device after the timer expires.

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