CN104575187A - Apparatus for the study of vertical plane dynamics - Google Patents

Abstract

The invention belongs to the field of devices for vertical plane dynamics research, and particularly relates to a dynamics device for researching circular motion. The invention discloses a device which is characterized in that a thin wire is tied with a heavy object to do circular motion on a vertical plane, experimental phenomena and theories do not accord with each other, and in order to explain the phenomena and prove the correctness of the theories, the invention provides a device which comprises the following components: a device for vertical plane dynamics research, including vertical panel, characterized by: an adsorption plate that is used for adsorbing the permanent magnet of vertical panel fixed connection, still include a magnetism post, magnetism post one end is adsorbed in adsorption plate, a fine rule of magnetism post other end bolt, the upper end bolt of fine rule in magnetism post, a heavy object is hung to the lower extreme of fine rule, vertical panel is equipped with one and runs through vertical panel just, the hole of reverse side, downthehole being equipped with is used for spouting the fire so that the first nozzle of burning off the fine rule as early as possible after the skew balanced position of fine rule, and the direction of spouting fire of first nozzle is: perpendicular to both the vertical panels and the thin lines.

Description

Apparatus for the study of vertical plane dynamics

technical field

The invention belongs to the field of devices used for vertical surface dynamics research, in particular to the dynamics device involved in the research of circular motion.

Background technique

A thin wire is tied to a heavy object to move in a circle on a vertical plane. When the weight is at its lowest point, the pulling force is greater than gravity, and the pulling force at the lowest point is the largest. The prior art discloses a device for studying circular motion: a vertical panel, located at the lower end of the vertical panel for supporting the base of the vertical panel, the vertical panel is made of iron plate, and also includes a permanent magnet, shaped It is a columnar magnetic column, one end of the magnetic column is adsorbed on the vertical panel, the other end of the magnetic column is bolted to a thin wire, the upper end of the thin wire is bolted to the magnetic column, and a heavy object is hung from the lower end of the thin wire. The method of using the device: firstly, the weight is raised to a certain height, and: 1, the thin line is in a straight state; 2, the thin line deviates from the vertical position. In the second step, the weight is released, and the weight begins to move in the shape of a circular arc, ie: part of a circular motion. Selecting a suitable release position can achieve such an effect: releasing a heavy object at this position can just pull down the magnetic column. The theoretical analysis is as follows: use T to represent the pulling force on the weight, G to represent the gravity on the weight, m to represent the mass of the weight, v to represent the speed of the weight passing through the lowest point, and r to represent the radius of the circular motion of the weight , deduced to get , so the conclusion that the greater the velocity v at the lowest point is, the greater the pulling force T is. Use this experiment to help explain: the magnetic column is pulled down, indicating that the pulling force T is greater than the gravity. The experimenter recorded a video of the experiment, and when playing the video frame by frame, he found that the magnetic column did not fall when the weight was at the lowest point, but the magnetic column fell after it clearly passed the lowest point. The experimenter repeated the experiment many times, recorded the video and played it frame by frame each time, and found this phenomenon. This phenomenon does not match the theory. This phenomenon has not been discovered before: it can only be observed by slow playback. It takes about 0.2 seconds from the weight passing through the lowest point to the magnetic column falling down. The time of 0.2 seconds is about 1/8 of the period of the single pendulum of the heavy object suspended by the device. In this 0.2 second, the distance traveled by the heavy object is about 2/3 of the amplitude, and the angle between the thin line and the vertical direction It's about 40 degrees. Therefore, usually this phenomenon cannot be observed in terms of time, but it can be observed from the distance of the weight from the equilibrium position during slow playback.

Strictly speaking, the experiment does not match the theory, and the experimental device is not suitable for the teaching of circular motion dynamics. In other words: to develop a new device that can demonstrate the experiment that the pulling force at the lowest point is greater than gravity, and overcome the above defects.

Since new devices are to be developed, it is necessary to know where the problems of existing devices are. There are two theories: 1. It takes time for the thin wire to deform, and this time is about 0.2s. After the thin wire is completely deformed, the magnetic column is pulled down by a greater pulling force. 2. The magnetic column began to fall when the weight passed the lowest point. However, the length of the magnetic column was not long enough. After 0.2 seconds, it was obvious that the magnetic column fell down. Both statements sound plausible. It is a very complicated theoretical issue to use theoretical knowledge to determine which statement is correct.

There are other explanations for this phenomenon, and those explanations can be directly ruled out through theoretical analysis, so they will not be described in this specification.

The present invention proposes a device, which can: 1. Verify which of the above two statements is correct. 2. Overcome the shortcomings of the existing devices, and achieve the beneficial effect that the experimental phenomenon is consistent with the theory.

Contents of the invention

The technical solution adopted by the present invention to overcome the deficiencies in the prior art is:

A device for dynamics research on a vertical surface, comprising a vertical panel, located at the lower end of the vertical panel for supporting the base of the vertical panel, characterized in that: the vertical panel is made of refractory material, and the vertical panel is fixedly connected to a For the adsorption plate that absorbs the permanent magnet, the surface of the adsorption plate used to absorb the permanent magnet is a vertical plane,

It also includes a columnar magnetic column made of permanent magnets, one end of the magnetic column is adsorbed on the adsorption plate, and the other end of the magnetic column is bolted to a thin wire.

The upper end of the thin wire is bolted to the magnetic column, and a weight is suspended from the lower end of the thin wire. The thin wire is made of a material that is easy to burn.

The vertical panel is provided with a hole that runs through the front and back of the vertical panel, and the hole is provided with a first nozzle for spraying fire so as to burn the thin line as early as possible after the thin line deviates from the equilibrium position, and the fire spraying direction of the first nozzle is : Perpendicular to both vertical panels and thin lines.

The position of the hole can be: obliquely above the weight, and: close to, but not coincident with, the vertical line where the thin line is located.

The shape of the hole can be: arc shape.

It may also include: a second nozzle arranged symmetrically to the first nozzle with the vertical plane passing through the thin line as a plane of symmetry, and the fire spraying direction of the second nozzle is: perpendicular to the vertical panel and perpendicular to the thin line.

The thin thread may be cotton thread.

The adsorption plate can be made of iron.

The shape of the magnetic column can be a cylinder.

The invention has a simple structure, and the invention can be used to do relevant experiments, so that the experimental phenomena can perfectly match the theoretical analysis.

Description of drawings

Figure 1 is a front view of the prior art.

Fig. 2 is a test chart of the prior art.

Fig. 3 is a front view of Embodiment 1 of the present invention.

Fig. 4 is a test diagram of Embodiment 1 of the present invention.

Fig. 5 is a test diagram of Embodiment 1 of the present invention.

Fig. 6 is a partially enlarged view of Embodiment 1 of the present invention.

Fig. 7 is a partially enlarged view of Embodiment 2 of the present invention.

Fig. 8 is a front view of Embodiment 3 of the present invention.

In the figure: 1-vertical panel, 2-base, 3-magnetic column, 4-thin wire, 5-weight, 6-adsorption plate, 7-hole, 8-first nozzle, 9-second nozzle.

Detailed ways

Accompanying drawing 1,2 are the front view and side view of prior art respectively.

Embodiment one

Referring to accompanying drawing 3, it is a front view of the present invention, and accompanying drawing 4 is a side view of the present invention. FIG. 5 is a side view of the present invention. In FIG. 5 , a range is surrounded by a dotted line, and these ranges are enlarged in FIG. 6 , or in other words, FIG. 6 is a partially enlarged view of FIG. 5 . These figures express:

The device used for vertical surface dynamics research includes a vertical panel 1, which is located at the lower end of the vertical panel 1 and is used to support the base 2 of the vertical panel 1. It is characterized in that: the vertical panel 1 is made of refractory material, and the vertical panel The panel 1 is fixedly connected with an adsorption plate 6 for absorbing the permanent magnet, and the surface of the adsorption plate 6 for absorbing the permanent magnet is a vertical plane,

It also includes a columnar magnetic column 3 made of permanent magnets, one end of the magnetic column 3 is adsorbed on the adsorption plate 6, and the other end of the magnetic column 3 is bolted to a thin wire 4,

The upper end of the thin wire 4 is bolted to the magnetic column 3, and a weight 5 is suspended from the lower end of the thin wire 4, and the thin wire 4 is made of a material that is easy to be blown.

The vertical panel 1 is provided with a hole 7 that runs through the front and back of the vertical panel 1, and the hole 7 is provided with a first nozzle 8 for spraying fire so as to burn the thin wire 4 as soon as possible after the thin wire 4 deviates from the equilibrium position, and the second The flame spraying direction of a nozzle 8 is: not only perpendicular to the vertical panel 1, but also perpendicular to the thin line 4.

The position of the hole 7 is: obliquely above the weight 5, and: close to, but not coincident with, the vertical line where the thin line 4 is located.

Explanation: Nozzles: The first nozzle 8 and the second nozzle 9 described in the present invention all refer to fire-spraying nozzles, and fire-spraying nozzles belong to the prior art, such as the nozzles introduced on the following webpage:

http://detail.tmall.com/item.htm?spm=a230r.1.14.18.RhvunH&id=40119733829&ad_id=&am_id=&cm_id=140105335569ed55e27b&pm_id=&abbucket=5

http://item.taobao.com/item.htm?spm=a230r.1.14.279.RhvunH&id=16026116927&ns=1&abbucket=5#detail

http://item.taobao.com/item.htm?spm=a230r.1.14.212.RhvunH&id=39322048663&ns=1&abbucket=5#detail

http://item.taobao.com/item.htm?spm=a230r.1.14.145.RhvunH&id=38722875361&ns=1&abbucket=5#detail

http://item.taobao.com/item.htm?spm=a230r.1.14.34.SX1kPc&id=18445364256&ns=1&abbucket=5#detail

http://detail.tmall.com/item.htm?spm=a230r.1.14.59.SX1kPc&id=13974025302&abbucket=5

Because the above-mentioned webpage is edited by the merchant of www.taobao.com, there is no guarantee that the above-mentioned webpage will always be displayed as a nozzle, and perhaps one day the merchant will edit the webpage as other products.

How to allow the nozzle to spray fire belongs to the prior art, such as oxyacetylene combustion and spraying fire, such as a portable propane fire spraying device, which are all prior art. The flame that the nozzle sprays can have the size of accessory device to regulate flame, makes flame very fine, and this is also prior art.

How to use: Adsorb the magnetic column 3 on the adsorption plate 6, the adsorption plate 6 can be made of iron, do not spray fire first, let the weight 5 deviate from the equilibrium position, and ensure that the shape of the thin line 4 is a straight line, and ensure that the thin line 4 Parallel to the vertical panel 1, then release the weight 5, and find this position through multiple experiments: when the weight 5 is released at this position, the weight 5 can just pull down the magnetic column 3 when moving in a circular arc. Mark the location. For the convenience of expression, this position is recorded as A position.

Squeeze the weight 5 with your hands so that the weight 5 is at position A, then let the nozzle spray fire and adjust the size of the flame so that the firepower of the flame is concentrated and the flame is thin.

Release the weight 5 so that the thin wire 4 is immediately cut off by the flame just after passing through the vertical direction.

The full name of the above demonstration process is video, and then play it at a slow speed. You can see that the thin wire 4 is blown as soon as it passes through the vertical direction. At the same time, the pulling force generated by the thin wire 4 disappears, and the magnetic column 3 remains horizontal. The direction is adsorbed on the adsorption plate 6, and after about 0.2 seconds, it is obviously observed that the magnetic column 3 is toppled over.

This shows that: 1, using the prior art to do this experiment did not see that the heavy object 5 pulls down the magnetic column 3 when it is at the lowest point, not because the deformation of the thin wire 4 requires a corresponding time, but because the magnetic column 3 falls It is a process from slow to fast. In the initial stage of the fall, even if the video is played in slow motion, it is difficult to find that the magnetic column 3 is obviously toppled. With the device of the present invention, it can be proved that when the weight 5 is at the lowest point, the pulling force does have a maximum value, and the pulling force is greater than the weight of the weight 5 .

The position of the hole 7 is: obliquely above the weight 5, and: close to, but not coincident with, the vertical line where the thin line 4 is located. The word close is usually an unclear expression, but through the above introduction, those skilled in the art should understand that close refers to the position where the thin wire 4 is burnt as soon as possible after the thin wire 4 passes through the vertical position. Why can't it be too late to blow the thin wire 4? Because the thin wire 4 was blown too late, when the video was played at a slow speed, it was still seen that the heavy object 5 passed the lowest point obviously, and the magnetic column 3 still did not fall down. Because the flame sprayed by the nozzle has a certain width, the flame cannot burn the thin wire 4 when the thin wire 4 is in the vertical direction. To achieve such effects: 1. The moment the thin wire 4 passes through the vertical position, the flame burns the thin wire 4 continuously. 2. After the thin wire 4 passes through the vertical position, the thin wire 4 is burned as early as possible. After such an explanation, those skilled in the art can understand the meaning of the word "near", and the expression "near" becomes clear. If you still feel that the word "near" is not clear, it can be expressed as: the position of the hole 7 is: above the balance position of the weight 5, the vertical direction is 1-3 cm away from the upper end of the weight 5, and: the horizontal direction is vertical to the thin line 4. Straight line 1-4cm.

Why not cut the thin wire 4 with a knife? Although the knife can cut the thin wire 4, the knife also changes the radius of the circular motion of the weight 5 at the same time, so that the pulling force increases, and the magnetic post 3 falls down under this situation. Column 3 is the result of slower pouring.

Those skilled in the relevant art will know that the flame contacts the thin wire 4 rather than the nozzle itself contacting the thin wire 4 .

Since the nozzle temperature is very high, the vertical panel 1 is made of refractory material. Such as tiles for architectural installations. Refractory materials are often not attracted by permanent magnets, so the vertical panel 1 is fixedly connected with an adsorption plate 6 for absorbing permanent magnets. In order to ensure that the magnetic column 3 is horizontal, the surface of the adsorption plate 6 for absorbing the permanent magnet can be a vertical plane. The shape of the magnetic column 3 can be a cylinder.

The flame spraying direction of the first nozzle 8 is: not only perpendicular to the vertical panel 1 , but also perpendicular to the thin line 4 . The flame ejected from the nozzle exerts a certain force on the thin wire 4, so burning the thin wire 4 perpendicular to the thin wire 4 is a way to reduce the error.

How the first nozzle 8 is installed in the hole 7 is a prior art. It can be fixedly arranged or connected in a detachable manner. It is also possible to use a hand-held welding torch to only allow the nozzle to stretch into the hole 7.

Using a flame to burn the thin wire 4, if you only look at this method, there is no creativity at all. But, the technical problem to be solved in the present invention is not how to cut off the thin wire 4, but: 1, verify which of the two statements is correct. 2. Provide a technical solution that is consistent with experiment and theory. Finding a problem that has never been seen before is creative in itself.

The thin wire 4 can be blown off in a very short time by spraying fire with the nozzle. Thin thread 4 is best to use cotton thread, and the cotton thread will burn almost instantly when it encounters the flame from the nozzle.

Since the present invention refers to a nozzle capable of spraying fire, those skilled in the art should know that when the present invention is used, it must be equipped with auxiliary equipment such as a gas supply device, a gas delivery pipeline, a gas volume or an oxygen volume regulating device, which are existing technology.

Embodiment two

Referring to accompanying drawing 7, it is the technical scheme optimized by accompanying drawing 6 of the present invention. It also includes: taking the vertical plane passing through the thin line 4 as a plane of symmetry, and a second nozzle 9 symmetrically arranged with the first nozzle 8, and the fire spraying direction of the second nozzle 9 is: both vertical to the vertical panel 1, and vertical in thin line 4.

Only one nozzle is used to burn the thin wire 4, and there is a shortcoming: the ejected flame will make the thin wire 4 receive a small impulse, and the direction of this impulse is perpendicular to the vertical panel 1 and away from the vertical panel 1. Even so, Still let some observers (students) raise doubts, they believe that the impulse exerted by the flame on the thin wire 4 affects the force on the thin wire 4, and then the thin wire 4 pulls down the magnetic column 3. There is some truth to this claim: because the flames did give the thin line 4 an impulse, albeit a very, very small one. In order to overcome this little momentum, another nozzle can be provided, that is, the second nozzle 9, the flame emitted by the second nozzle 9 intersects with the flame emitted by the first nozzle 8, and at the intersection point, it is the position where the thin line 4 passes. In this way, the thin wire 4 is not subjected to the impulse exerted by the flame in the direction perpendicular to the thin wire 4 or along the direction of the thin wire 4 . Of course, when the two flames spray fire towards each other, the fire spraying time should be shortened as much as possible to avoid damage to the equipment.

How to fix the second nozzle 9 belongs to the prior art, and a bracket can be used, and a hand-held welding torch can be used---of course, the hand must be held firmly.

Embodiment three

Referring to accompanying drawing 8, the shape of the hole 7 is: arc shape, and the hole 7 of the arc shape is located above the weight 5 . One advantage of this design is that the position of the fire point can be adjusted. And the center of the arc is located at the junction of the magnetic column 3 and the adsorption plate 6, and the radius of the arc is slightly smaller than the length of the rope. Slightly smaller than—these three words are generally unclear, but in this application, slightly smaller means that the position where the thin wire 4 is blown is preferably close to the position of the weight 5 . The thin wire turns at the same angle, and the farther it is from the center of the circle, the longer the arc length it travels. If the thin wire is burnt at a position very close to the center of the circle, the deflection angle of the thin wire may be too large. For this understanding, please refer to the explanation of the word "approach" in this manual.

Each of the above embodiments can be used in reasonable combination.

Those skilled in the relevant art should know that the position where the thin wire 4 is blown is preferably close to the position of the weight 5 .

Cotton thread refers to a thin thread made of cotton, which is easily burned.

The invention has a simple structure, is beneficial to explore some problems of dynamics, and as an auxiliary experimental device, the experimental phenomenon can be consistent with the theory.

Claims (1)

1. for the device of vertical plane dynamics research, comprise vertical panel, be positioned at vertical panel lower end for supporting the base of vertical panel, it is characterized in that: vertical panel is made up of fire resistive material, vertical panel is fixedly connected with one for adsorbing the adsorption plate of permanent magnet, adsorption plate is perpendicular for adsorbing that face of permanent magnet

Also comprise that be made up of permanent magnet, shape is a column magnetic post, magnetic post one end is adsorbed in adsorption plate, magnetic post other end bolt fine rule,

The upper end of fine rule is bolted to magnetic post, and the lower end of fine rule hangs a weight, and fine rule is made up of the material being easy to blow,

Vertical panel is provided with the hole that runs through vertical panel positive and negative, be provided with for flame to blow the first jet of fine rule after fine rule departs from equilibrium position as early as possible in hole, and the flame direction of first jet is: both perpendicular to vertical panel, again perpendicular to fine rule.