CN209168492U - A kind of centripetal force photoelectric measurement demonstrator - Google Patents

Abstract

In order to quickly and accurately measure centripetal force size, preferably verifying centripetal force formula, the utility model provide a kind of centripetal force photoelectric measurement demonstrator, are related to a kind of physics teaching in secondary school laboratory apparatus.The demonstrator drives scale rotating plate and swing ball to do stable uniform circular motion by slowspeed machine, swing ball movement becomes motor control from original manually controlling, circular motion of the movement of swing ball closer to standard, " servo-actuated " structure being made of scale rotating plate, swing ball and photographic device can real-time and accurately measure swing ball drift angle, and circular motion cycle is measured using photoelectric door, experimentation is promoted to quantitative measurment by qualitative verifying, experiment method stability height, favorable repeatability, experimental error greatly reduces, and is more advantageous to the development of Experimental Research teaching.

Description

A kind of centripetal force photoelectric measurement demonstrator

Technical field

The utility model relates to a kind of physics teaching in secondary school and laboratory apparatus, especially a kind of centripetal force photoelectric measurement demonstration Instrument.

Background technique

Currently, student lacks real experiences, and suitable technology hand is lacked in teaching in the centripetal force teaching of Middle School Physics Section, student understands in study and using having certain difficulty in centripetal force knowledge, learning initiative and interest is not high.In senior middle school " physics " required 2(people teaches version) " centripetal force " section in, the experiment of verifying centripetal force expression formula is conical pendu0.This on teaching material It is a experiment in terms of design, principle, operation and the property of participation of student all very well, but during field research there is also several points not Foot: 1, because being to use hand-motion bead, bead is difficult with the naked eye to find out the motion profile of bead not along some circular motion It is round；2, since bead movement is irregular, it is difficult to determine and uses which circle as marked circle, the randomness of practical operation is very big；3, With the naked eye estimate movement circle number and the time of bead, it is easy to malfunction；4, the circle number recorded is usually no more than 5 circles, and bead will Slowly stop；5, the calculation amount for calculating resultant force is bigger.The experimental results error that student measures is very big, and teacher will do in teaching It is many to explain, cause student not high to the confidence level of experiment, teaching efficiency is not achieved.

Summary of the invention

In order to demonstrate centripetal force phenomenon visual in imagely, centripetal force expression formula is verified, the utility model provides a kind of centripetal Power photoelectric measurement demonstrator can be made uninteresting theoretical knowledge become vivid specific, be learned by experimental verification centripetal force expression formula Life is acceptant.The movement speed of swing ball is controlled by slowspeed machine, and the movement of swing ball can be made closer to uniform circular motion, drop The control difficulty of low experimenter, and it is easy to operate, it is easy to the overall process that student participates in experiment.

The utility model, which solves scheme used by its technical problem, mainly the following.

1. this centripetal force photoelectric measurement demonstrator is mainly by switching, adjusting the speed knob, Switching Power Supply, slowspeed machine, timing Device, partition, photoelectric door, shading bar, scale rotating plate, cycloid, bracket, lightweight bracket, sliding slot, camera, adjusting nut, swing ball and The composition such as central rotating shaft, wherein switch, speed regulation knob, Switching Power Supply, slowspeed machine and timer are all screwed and are mounted on Above the partition of bracket, photoelectric door is fixedly mounted below the partition of bracket, and shading bar and scale rotating plate are all fixed on center and turn On axis and bilateral symmetry passes right through the middle position of photoelectric door when shading bar rotation.

2. the swing ball in the demonstrator is connected with cycloid, the other end of cycloid is fixed on zero groove on the right side of scale rotating plate Place is with a distance from central rotating shaftl, when the rotation of scale rotating plate, swing ball could obtain a drift angle.

It, can along the chute up and down 3. the camera in the demonstrator is fixed on the sliding slot of lightweight bracket by adjusting nut Adjusting position, lightweight bracket both ends then pass through adjusting nut and are fixed in the groove at scale rotating plate edge, can be along groove or so Adjusting position.

4. the shaft of the slowspeed machine in the demonstrator is connect with central rotating shaft, when motor operating, drive central rotating shaft, Shading bar, scale rotating plate, cycloid, swing ball, lightweight bracket and camera rotate together, and can control the revolving speed of central rotating shaft, by " servo-actuated " structure of scale rotating plate, swing ball and photographic device composition can real-time and accurately measure swing ball drift angle.

5. the camera in the demonstrator is the mini mobile camera that can be charged, carry wifi transmitting and can with plug-in card, Experimental implementation person can put video with mobile phone observation or electricity consumption gyrus in real time and record data；The supply voltage of slowspeed machine is 24V。

All conducting wires are hidden in the groove of partition.

The utility model has the beneficial effects that driving scale rotating plate and swing ball to be stable steady circular by slowspeed machine Movement, swing ball movement become motor control, the circular motion of the closer standard of the movement of swing ball, by carving from original manually controlling " servo-actuated " structure real-time and accurate measurement swing ball drift angle of rotating plate, swing ball and photographic device composition is spent, and using photoelectric door measurement circle Experimentation is promoted to quantitative measurment by qualitative verifying by all periods of motion, and experiment method stability height, favorable repeatability are real It tests error to greatly reduce, is more advantageous to the development of Experimental Research teaching.The principle and experimentation entirely tested are simple to operation, Student's property of participation is strong.

Detailed description of the invention

The present invention will be further described with reference to the accompanying drawings and examples.

Fig. 1 is the experimental principle figure of the utility model.

Fig. 2 is the structural schematic diagram of the utility model.

The structural schematic diagram of the utility model is as shown in Fig. 2, include that (1) switch (2) adjusts the speed knob (3) Switching Power Supply (4) Slowspeed machine (5) timer (6) partition (7) photoelectric door (8) shading bar (9) scale rotating plate (10) cycloid (11) bracket (12) lightweight Bracket (13) sliding slot (14) camera (15) adjusting nut (16) swing ball (17) trivet (18) adjustable support foot (19) center turns Axis.

Specific embodiment

The utility model proposes a kind of centripetal force photoelectric measurement demonstrators, can rapidly and accurately measure the pivot angle θ of bead And angular velocity omega, as shown in Figure 1, to obtain experimental result rapidly.

In this embodiment, first with graduated scale measure pendulum length L (as long as to measure cycloid long for rough measure, if Precise measurement then will add swing ball radius) and cycloid hitch point to motor rotary shaft center line distancel, adjust bottom two Adjusting nut is aligned cycloid with the zero graduation line of scale rotating plate under static state, to determine the initial position of cycloid.

Closure switch regulate the lightweight backing positions with camera (about 15 in this embodiment^OPlace), camera is opened, Rotation speed regulation knob makes motor slowly starting since low-grade, and swing ball and entire scale rotating plate is allowed to turn in the counterclockwise direction together It is dynamic, it ramps up, until the drift angle that cycloid and initial position can be observed is kept approximately constant when scale rotating plate stability of rotation, uses The drift angle registration θ on scale rotating plate at this time is observed in real time and recorded to mobile phone, former according to the experiment in the synthesis knowledge and Fig. 1 of power Li Tuke get

Resultant force suffered by swing ball can quickly be calculated。

After scale rotating plate stability of rotation, timer and photogate are opened simultaneously, is hidden when recording swing ball motion stabilization Frequency n and total shading time t of the polished rod by photoelectric door.The shading of shading bar each rotation twice, according to timer record Shading frequency n and total shading time t calculate the cycle T of swing ball movement,

The angular velocity omega of swing ball is calculated using circular motion formula,

It is using the circular motion radius that trigonometric function relational expression can calculate swing ball

Swing ball moving radiusCentripetal force formula is substituted into angular velocity omega

Centripetal force suffered by swing ball can quickly be calculated。

Because of the quality of swing ball in the entire experiment processIt remains unchanged, so It is not necessary to measuringSpecific value Come, calculated resultant forceAnd centripetal forceIt is all the expression formula containing m.It is repeated several times above-mentioned experimentation, it is relatively more every Secondary resultant forceAnd centripetal forceSize, can smoothly obtain experiment conclusion.

Claims (2)

1. a kind of centripetal force photoelectric measurement demonstrator, it is characterised in that the demonstrator is mainly by switching, adjusting the speed knob, switch electricity Source, slowspeed machine, timer, partition, photoelectric door, shading bar, scale rotating plate, cycloid, bracket, lightweight bracket, sliding slot, camera shooting The composition such as head, adjusting nut, swing ball and central rotating shaft, wherein switch, speed regulation knob, Switching Power Supply, slowspeed machine and timer It is all screwed above the partition for being mounted on bracket, photoelectric door is fixedly mounted below the partition of bracket, shading bar and scale Rotating plate is all fixed on central rotating shaft and bilateral symmetry, swing ball are connected with cycloid, and the other end of cycloid is fixed on scale rotating plate At zero groove on the right side, it is with a distance from central rotating shaftl, camera is fixed on the sliding slot of lightweight bracket by adjusting nut, It then can pass through adjusting nut along the chute and be fixed in the groove at scale rotating plate edge in up and down adjustment position, lightweight bracket both ends, It can be connect along groove left and right adjusting position, the shaft of slowspeed machine with central rotating shaft, when motor operating, center be driven to turn Axis, shading bar, scale rotating plate, cycloid, swing ball, lightweight bracket and camera rotate together, and can control the revolving speed of central rotating shaft.

2. a kind of centripetal force photoelectric measurement demonstrator according to claim 1, it is characterised in that the camera shooting in the measuring instrument Head is the mini mobile camera that can be charged, and the supply voltage of slowspeed machine is 24V.