CN109448511A - A kind of centripetal force experimental provision - Google Patents

Abstract

In order to quickly and accurately measure centripetal force size, preferably verifying centripetal force formula, the present invention provides a kind of centripetal force experimental provision, is related to a kind of physics teaching in secondary school and laboratory apparatus.According to design scheme provided by the present invention, the shading number that needs to carry out dynamic measurement, shading time are measured automatically by timer, and cycloid to the pulling force of swing ball and the pointer position registration of spring scale is directly read on the dial of fixed spring scale when rotation.The experiment reading mode that the experiment takes dynamic to staticize reduces the difficulty of experimental data acquisition, improves the operability of experiment, and can organically combine with traditional experiment, is more advantageous to the development of Experimental Research teaching.

Description

A kind of centripetal force experimental provision

Technical field

The present invention relates to a kind of physics teaching in secondary school and laboratory apparatus more particularly to a kind of centripetal force experimental provisions.

Background technique

Teach version in the required 2(people of senior middle school's " physics ") " centripetal force " section in, the experiment of verifying centripetal force expression formula is round Conical pendulm, conical pendu0 experiment understand student excessively abstract, exist clearly disadvantageous in actual operation, are to use hand-motion first Bead, is difficult some circular motion for making bead on paper, and bead does elliptic motion mostly in the horizontal plane；Then bead is being done When circular motion, there are a certain distance between paper, can not determine and be moved on which circumference actually, the radius of measurement with it is small The radius error of ball actual motion is very big；There are also the run durations of conical pendu0 and circle number to sentence by student's stopwatch and naked eyes to measure Disconnected, experimental error is larger, and student can only be forced to receive experiment conclusion in unapprehended situation, and the effect given lessons in this way is not It is highly desirable.

Summary of the invention

In order to quickly and intuitively demonstrate centripetal force experiment, overcome the shortcomings of it is above, make experiment intuitive and reliability Enhancing, the present invention provides a kind of centripetal force experimental provision, is related to a kind of physics teaching in secondary school and laboratory apparatus.The experimental provision packet Include bracket, fixed screw, spring scale, turntable, fixed pulley, shaft, empty slot, cycloid, swing ball, motor, anti-dazzling screen, timer, The parts such as leveling serew, speed-regulating switch, master switch, photoelectric door and level meter, entire experimental provision use as a whole.

According to design scheme provided by the present invention, the swing ball movement of the experimental provision becomes electricity from original manually controlling Motivation control, the horizontal movement track of swing ball keep swing ball movement more stable, it is easier to read the big of power closer to standard round Small, the run duration of swing ball and the circle number of movement also switch to timer automatic measurement by manual measurement, and experimental error greatly reduces. The present invention, which solves scheme used by its technical problem, mainly the following.

1, the experimental provision is mainly by bracket, spring scale, turntable, fixed pulley, shaft, cycloid, swing ball, motor, shading The composition such as piece, timer, leveling serew, speed-regulating switch, master switch, photoelectric door and level meter, wherein four fixed pulleys are symmetrically solid The both sides on shaft top are scheduled on, two long two is short, and position and cycloid direction are tangent, and cycloid is fixed on disk diameter both ends, along perpendicular Histogram is connected to around fixed pulley with swing ball, and anti-dazzling screen is fixed on shaft lower part, drives shaft to provide active force, band by motor Movable pendulum ball rotation, so that turntable be driven to rotate.

2, fixed pulley, turntable, swing ball, cycloid described in the experimental provision all keep both sides pair about the central axis of shaft Claim.

3, spring scale described in the experimental provision is fixed on the top plate of bracket with fixed screw, the dial of spring scale The left side is elastic force scale, and the right is length scale, and zero groove of both sides scale is in same position.

4, the hook of spring scale described in the experimental provision is fixed on the bearing cap among turntable, turntable rolling bearing lid It does not rotate, the hook of spring balance can only move along the vertical direction under the action of cycloid.

5, there are one and empty slot similar in cycloid position among shaft described in the experimental provision, convenient for using graduated scale from empty slot In pass through to measure the distance between two cycloids.

6, master switch, speed-regulating switch and motor described in the experimental provision are fixedly arranged at the middle layer partition of bracket On, timer, photoelectric door and level meter are fixedly arranged on the bottom plate of bracket.

It is low in cost, easy to operate that the beneficial effects of the invention are as follows the experimental provisions, and demonstration centripetal force experiment effect is obvious, Error is small.The quality m of swing ball is remained unchanged during the experiment, according to design scheme provided by the present invention, is moved The shading number of state measurement, shading time are measured automatically by timer, pulling force and spring of the cycloid to swing ball when rotation The pointer position registration of scale is directly read on the dial of fixed spring scale.The experiment takes dynamic to staticize Reading mode is tested, the difficulty of experimental data acquisition is reduced, improves the operability of experiment, the principle and reality entirely tested It is little with the experiment difference on teaching material to test process, simple to operation, student's property of participation is strong.

Detailed description of the invention

Present invention will be further explained below with reference to the attached drawings and examples, and wherein Fig. 1 is structural schematic diagram of the invention；Figure 2 be static measurement schematic diagram of the invention；Fig. 3 is dynamic instrumentation plan of the invention.

Specific embodiment

The invention proposes a kind of centripetal force experimental provisions, centripetal force experiment can fast, be intuitively demonstrated, thus fast Speed obtains experimental result.

Structural schematic diagram of the invention as shown in Figure 1, the device include bracket (1), fixed screw (2), spring scale (3), Turntable (4), fixed pulley (5), shaft (6), empty slot (7), cycloid (8), swing ball (9), motor (10), anti-dazzling screen (11), timing The parts such as device (12), leveling serew (13), speed-regulating switch (14), master switch (15), photoelectric door (16), level meter (17), wherein Four fixed pulleys (5) are symmetrically fixed on the both sides on shaft (6) top, and two long two is short, and position and cycloid direction are tangent, cycloid (8) turntable (4) diameter both ends are fixed on, are connected along the vertical direction around fixed pulley (5) with swing ball (9), anti-dazzling screen (11) is fixed It in shaft (6) lower part, drives shaft (6) to provide active force by motor (10), swing ball (9) rotation is driven, to drive turntable (4) it rotates；Fixed pulley (5), turntable (4), swing ball (9), cycloid (8) all keep both sides symmetrical about the central axis of shaft (6)；Bullet Spring scale (3) is fixed on the top plate of bracket (1) with fixed screw, and the dial left side of spring scale (3) is elastic force scale, and the right is Length scale, zero groove of both sides scale is in same position；The centre of turntable (4) is ball bearing, very smooth, spring scale (3) hook is fixed on the intermediate bearing cap of turntable (4), and turntable (4) rolling bearing lid does not rotate, the hook of spring balance (3) It can only be moved along the vertical direction under the action of cycloid (8)；There are one and empty slot similar in cycloid (8) position among shaft (6) (7), it is convenient for being passed through from empty slot (7) with graduated scale to measure the distance between two cycloids；Motor (10), speed-regulating switch (14) and Master switch (15) is fixedly arranged on the middle layer partition of bracket (1), and timer (12), photoelectric door (16) and level meter (17) are all It is fixedly mounted on the bottom plate of bracket (1).

In the present embodiment, firstly, adjusting leveling serew, level meter is observed, so that whole device is in equilibrium state, takes Lower two swing balls, are adjusted to the pointer of spring balance the position of zero groove；Then swing ball is hung on cycloid, wait it is static after, such as Fig. 2 It is shown, record the registration of the elastic force on spring scale dialWith length registration, pendulum length when measuring static with graduated scale As long as (rough measure measures cycloid length, and the radius r) of swing ball is added to precise measurement, then is passed through and turned with graduated scale The empty slot (7) of axis (6) measures the distance of two cycloids, according to the synthesis knowledge of power, the gravity of ballWith elastic forceRelationship For, then。

Slowly start motor since low-grade, swing ball and entire turntable is allowed to rotate counterclockwise together, adjusts governor, by When gradually accelerating to turntable stability of rotation, timer and photogate are opened simultaneously, at this moment the pointer registration of spring scale is also stable, Record the shading number of anti-dazzling screenWith corresponding total shading time, at this time swing ball rotation period be, then angle is fast Degree；Elastic force registration shown in the pointer of spring scale is recorded simultaneouslyWith length registration, as shown in figure 3, spring at this time The spring elongation of scale, pulling force of the cycloid to swing ball, resultant force suffered by swing ball, Then, the moving radius of swing ball can be calculated using geometry teaching, swing ball Moving radius R and angular speedSubstitute into centripetal force formulaCentripetal force can quickly be calculated。

Governor is adjusted, above-mentioned experimentation, more each resultant force are repeated several timesAnd centripetal forceSize, It can smoothly obtain experiment conclusion.

The quality m of swing ball is remained unchanged during the experiment, needs to measure and record、、WithIt is all quiet State measurement；Need to carry out dynamic measurement have N, t,With, wherein N and t is measured automatically by timer,WithIt is then directly to be read on the dial of the spring scale of repacking, also corresponds to static measurement, so experimental error very little.

Claims (5)

1. a kind of centripetal force experimental provision, it is characterised in that the experimental provision includes bracket, spring scale, turntable, fixed pulley, turns The portions such as axis, cycloid, swing ball, motor, anti-dazzling screen, timer, leveling serew, speed-regulating switch, master switch, photoelectric door and level meter Point, wherein four fixed pulleys are symmetrically fixed on the both sides on shaft top, two long two is short, and position and cycloid direction are tangent, cycloid Disk diameter both ends are fixed on, are connected along the vertical direction around fixed pulley with swing ball, anti-dazzling screen is fixed on shaft lower part, by electronic Machine drives shaft to provide active force, anti-dazzling screen and swing ball rotation is driven, so that turntable be driven to rotate.

2. a kind of centripetal force experimental provision according to claim 1, it is characterised in that the fixed pulley, turntable, swing ball, Cycloid all keeps both sides symmetrical about the central axis of shaft.

3. a kind of centripetal force experimental provision according to claim 1, it is characterised in that the spring scale fixed screw It is fixed on the top plate of bracket, the dial left side of spring scale is elastic force scale, and the right is length scale, zero quarter of both sides scale Line is in same position.

4. a kind of centripetal force experimental provision according to claim 1, it is characterised in that the hook of the spring scale is fixed On the bearing cap among turntable, turntable dynamic bearing lid is motionless, and the hook of spring balance can only be vertically square under the action of cycloid To movement.

5. a kind of centripetal force experimental provision according to claim 1, it is characterised in that have one and pendulum among the shaft Empty slot similar in line position, convenient for graduated scale two cycloids are measured from passing through in empty slot between distance.