CN110718124A

CN110718124A - Accurate simple pendulum experimental apparatus

Info

Publication number: CN110718124A
Application number: CN201911117642.9A
Authority: CN
Inventors: 郭瑞超; 许同杰; 解传梅; 陈庆东; 范吉超; 张春旺; 邸达文
Original assignee: Binzhou University
Current assignee: Binzhou University
Priority date: 2019-11-15
Filing date: 2019-11-15
Publication date: 2020-01-21

Abstract

The invention discloses an accurate simple pendulum experimental device, which comprises a base, a lead screw vertical plate, a cycloid and a pendulum bob, wherein the lead screw vertical plate is fixed on the base, and the accurate simple pendulum experimental device is characterized in that: a winding seat is fixed on the upper fixed table, and the pendulum bob is fixed at the lower end of the cycloid; be provided with the slip table on the lead screw, be fixed with on the slip table and carry out the photoelectric door that detects to the pendulum through the minimum position constantly, set up the laser hole that aligns with the minimum position of pendulum on the photoelectric door, be fixed with on the lead screw riser and carry out the vertical scale of demarcation to the length of cycloid. The simple pendulum experimental device realizes the release of the pendulum bob at any transverse position and any height without initial speed, and meets the law of energy conservation in solving; because the length of the cycloid and the swing distance can be measured by the scale, the swing angle can be obtained by reversely solving the trigonometric function, and the measurement error of the swing angle is greatly reduced. The experimental device is low in cost, very suitable for large-batch physical experiments of single pendulum of students and wide in economic development prospect.

Description

Accurate simple pendulum experimental apparatus

Technical Field

The invention relates to a simple pendulum experimental device, in particular to an accurate simple pendulum experimental device which can accurately determine the rotation center, the pendulum angle and the pendulum length of a cycloid and has no initial speed when a pendulum ball is released.

Background

The simple pendulum test is a simple but very important experiment in basic physics of university and physics teaching of science, namely: a heavy hammer with the mass m is lifted by a thin wire with the negligible weight to swing left and right, and when the swing angle is 0 degree, the magnitude of the resultant external force borne by the heavy hammer is equal to the gravity of the small ball. A rope and a ball can form a simple pendulum experiment and can roughly estimate the local gravity acceleration. The existing university physical simple pendulum experimental device basically comprises the following operation steps: firstly, according to the energy conservation during the vibration of a simple pendulum, the pendulum angle and the cycloid are required to be measured; and secondly, when the cycloid reaches a certain swing angle, releasing the pendulum bob, and estimating the local gravity acceleration value by changing the swing angle and the cycloid length for many times. However, the experiment is slightly insufficient in data accuracy and operation content, and is not beneficial to students to learn and understand the motion process and the principle of the simple pendulum: for the swing center of the cycloid, the existing swing tester can not accurately center, so that the measurement of the swing angle and the cycloid has larger deviation, when the pendulum bob is released, the initial speed during the release is increased undoubtedly due to the fact that a certain swing angle releasing mode is pulled up manually, and the energy conservation law during solving acceleration is not satisfied. Therefore, the existing tester has large errors in key swing measurement parameters, and the solving precision is greatly influenced.

Disclosure of Invention

In order to overcome the defects of the technical problems, the invention provides an accurate simple pendulum experimental device which can accurately determine the cycloid rotation center, the pendulum angle and the pendulum length and has no initial speed when a pendulum ball is released.

The accurate simple pendulum experiment device comprises a base, a lead screw vertical plate, a cycloid and a pendulum bob, wherein the lead screw vertical plate is fixed on the base; the method is characterized in that: a winding seat is fixed on the upper fixing table, a cycloid is telescopically arranged on the winding seat, and a pendulum bob is fixed at the lower end of the cycloid; a sliding table is arranged on the screw rod and is in transmission fit with the screw rod through a thread pair, a guide rod is fixed on a vertical plate of the screw rod, the length direction of the guide rod is consistent with the length direction of the screw rod, and a guide groove matched with the guide rod is arranged on the sliding table; a photoelectric door for detecting the pendulum bob at the moment when the pendulum bob passes through the lowest point position is fixed on the sliding table, a laser hole aligned with the lowest point position of the pendulum bob is formed in the photoelectric door, and a vertical dividing ruler for calibrating the length of the cycloid is fixed on the vertical screw rod plate.

The accurate simple pendulum experimental device comprises a transverse pendulum releasing mechanism, wherein the transverse pendulum releasing mechanism consists of a horizontal guide rail, a lifting outer rod, a lifting inner rod and an elastic buckle, the horizontal guide rail is positioned right below the pendulum, and the length direction of the horizontal guide rail is consistent with the swinging direction of the pendulum; the outer lifting rod is arranged on the horizontal guide rail through a sliding block, the inner lifting rod is telescopically inserted into the outer lifting rod, and a fixing bolt for positioning the extension length of the inner lifting rod is fixed on the outer lifting rod; a transverse graduated scale for calibrating the horizontal distance between the initial point and the lowest point of the pendulum bob is fixed on the base or the horizontal guide rail;

the elastic buckle is fixed at the upper end of the lifting inner rod, and the central point of the elastic buckle, the central point of the pendulum bob at the lowest position and the central line of the horizontal guide rail in the length direction are positioned in the same plane; the elastic buckle is composed of two semicircular clamping rings, an extending part is arranged at the upper end of each semicircular clamping ring, the diameter of an inner cavity formed by the two semicircular clamping rings is smaller than that of the pendulum bob under the condition that the elastic buckle is not stressed, and the diameter of the inner cavity formed by the two semicircular clamping rings can be enlarged to be larger than that of the pendulum bob under the condition that the two semicircular clamping rings are pulled outwards by holding the extending part by hand.

According to the accurate simple pendulum experiment device, the rotating wheel for winding or releasing the cycloid is arranged on the winding seat, the winding seat is provided with a threaded hole with a downward opening, and the cycloid extends out through the threaded hole; and a cycloid fixing bolt for fixing the cycloid in the threaded hole is arranged in the threaded hole.

According to the accurate simple pendulum experiment device, the vertical plates of the screw rod are fixed on the base through the L-shaped fixing plate, the number of the guide rods is two, and the two guide rods are respectively positioned on two sides of the screw rod.

The invention has the beneficial effects that: according to the simple pendulum experiment device, the lead screw and the guide rod are arranged on the lead screw vertical plate, the sliding table is arranged on the lead screw through the thread pair, the winding seat is arranged on the upper fixing table, the photoelectric door is fixed on the sliding table, and the sliding table can be driven to ascend or descend by rotating the lead screw, so that the adjustment of the cycloid length is realized, the cycloid length can be obtained according to the vertical scale, and simple pendulum experiments with different cycloid lengths can be carried out; through setting up by horizontal guide, go up and down outer pole and interior pole, the horizontal pendulum release mechanism that the elasticity buckle formed, move on horizontal guide through going up and down the outer pole, and the lift of pole in going up and down, usable elasticity buckle fixes the pendulum at the initial point of simple pendulum experiment, the release of no initial velocity that the pendulum was in has been realized, can read the horizontal distance between pendulum initial position and the minimum point position through horizontal scale simultaneously, under the known condition of horizontal distance, cycloid length, can ask the pivot angle according to the trigonometric function.

The simple pendulum experimental device has the advantages that: the photoelectric door on the sliding table can stay at any position through the self-locking function of the screw thread matching of the lead screw, so that the time of the pendulum bob passing through the position of the vertical line can be accurately measured; the pendulum bob can be released at any transverse position and at any height without initial speed by matching the lifting rod arranged transversely with the pendulum bob in a centering manner with the elastic buckle, and the energy conservation law during solving is satisfied. Because the length of the cycloid and the swing distance can be measured by the scale, the swing angle can be obtained by reversely solving the trigonometric function, and the measurement error of the swing angle is greatly reduced. The accurate simple pendulum experiment device is low in cost, is very suitable for large-batch physical experiments of the simple pendulum of the students, and has wide economic development prospect.

Drawings

FIG. 1 is a perspective view of an accurate simple pendulum experimental setup of the present invention;

FIG. 2 is a front view of the precision simple pendulum experimental setup of the present invention;

FIG. 3 is a right side view of the precision simple pendulum experimental setup of the present invention;

FIG. 4 is a cross-sectional view of section A-A of FIG. 2;

FIG. 5 is a partial enlarged view of the position of the winding seat in the present invention;

FIG. 6 is a partial enlarged view of the position of the photogate of the present invention;

FIG. 7 is a schematic view of the mechanism of the lateral pendulum release mechanism of the present invention in cooperation with a base.

In the figure: the automatic lifting device comprises a hand crank 1, an upper fixing table 2, a lead screw vertical plate 3, a guide rod 4, a lead screw 5, a pendulum bob 6, a sliding table 7, a lower fixing table 8, a 9L-shaped fixing plate, a base 10, a horizontal guide rail 11, a horizontal graduated scale 12, a lifting outer rod 13, a lifting inner rod 14, an elastic buckle 15, a photoelectric door 16, a cycloid 17, a winding seat 18, a height adjusting bolt 19, a vertical graduated scale 20, an upper bearing 21, a lower bearing 22, a vertical plate fixing bolt 23, a rotating wheel 24, a cycloid fixing bolt 25, a photoelectric door fixing bolt 26 and a laser hole 27.

Detailed Description

The invention is further described with reference to the following figures and examples.

As shown in fig. 1, 2 and 3, which respectively show a perspective view, a front view and a right view of the precise simple pendulum experimental device of the present invention, fig. 4 shows a cross-sectional view of a section a-a in fig. 2, the simple pendulum experimental device shown is composed of a base 10, a vertical lead screw plate 3, a lead screw 5, a guide rod 4, an upper fixing table 2, a lower fixing table 8, a hand crank 1, a cycloid 17, a pendulum bob 6, a winding seat 18, a photoelectric door 16 and a transverse pendulum bob releasing mechanism, the base 10 plays a role in fixing and supporting, and the vertical lead screw plate 3 is fixed on the base 10 in a vertical state; the lead screw vertical plate 3 is fixed on the base 10 through an L-shaped fixing plate 9, and the L-shaped fixing plate 9 is fixedly connected with the lead screw vertical plate 3 and the base 10 through a vertical plate fixing bolt 23. Go up fixed station 2 and lower fixed station 8 and be fixed in the upper end and the lower extreme of lead screw riser 3 towards the side of base 10 respectively, the upper end of lead screw 5 sets up on last fixed station 2 through upper bearing 21, and the lower extreme of lead screw 5 sets up on lower fixed station 8 through lower bearing 22 to guarantee that lead screw 5 carries out the free rotation.

The quantity of guide bar 4 is two, and two guide bar 4 are located the both sides of lead screw 5 respectively to be fixed in on the lead screw riser 3, and the length direction of guide bar 4 is parallel with the length direction of lead screw 5. The sliding table 7 is matched with the screw rod 5 in a thread pair mode, and the thread pair between the sliding table 7 and the screw rod 5 has a self-locking function, so that the sliding table 7 stably stays at a corresponding height position. Be provided with the guide way with guide bar 4 matched with on the slip table 7, the upper end of lead screw 5 is fixed with crank 1, like this, rotates the in-process of lead screw 5 through crank 1, because guide bar 4 is spacing and guide effect to slip table 7 for slip table 7 goes up and down along the direction of height of lead screw 5. A vertical scale 20 is fixed on the vertical plate 3 of the screw rod, and the vertical scale 20 is used for calibrating the length of the cycloid 17.

The winding seat 18 is fixed on the upper fixed table 2, as shown in fig. 5, a partial enlarged view of the position of the winding seat in the present invention is shown, the winding seat 18 is provided with a rotating wheel 24, and the rotating wheel 24 is used for winding the cycloid 17 to realize the extension or shortening of the length of the cycloid 17 for changing the cycloid length of the simple pendulum experiment. A threaded hole which faces downwards vertically is formed in the winding seat 18, the cycloid 17 penetrates out of the threaded hole and is fixed through a cycloid fixing bolt 25 screwed into the threaded hole, and the uniqueness of the swing center of a simple pendulum experiment is guaranteed.

The shown photoelectric gate 16 is fixed on the sliding table 7, the photoelectric gate 16 is used for measuring the moment when the pendulum bob 6 passes through the lowest point, as shown in fig. 6, a partial enlarged view of the position of the photoelectric gate in the invention is given, the shown photoelectric gate 16 is in a U-shaped structure, so that the pendulum bob 6 at the lower end of the cycloid 17 passes through the U-shaped groove of the U-shaped photoelectric gate 16 to perform single pendulum motion in the single pendulum experiment process. The photoelectric door 16 is provided with a laser hole 27, and the laser hole 27 corresponds to the lowest point position of the pendulum bob 6 so as to measure the moment when the pendulum bob 6 passes through the lowest point. The shown photogate 16 is fixed to the slide table 7 via a photogate fixing bolt 26.

The transverse pendulum releasing mechanism comprises a horizontal guide rail 11, a lifting outer rod 13, a lifting inner rod 14, an elastic buckle 15 and a height adjusting bolt 19, wherein the horizontal guide rail 11 is located right below the pendulum 6, and the length direction of the horizontal guide rail 11 coincides with the projection of the swinging path of the pendulum 6 on the base 10 in the simple pendulum experiment process. The outer lifting rod 13 is arranged on the horizontal guide rail 11 through a sliding block, so that the outer lifting rod 13 can move along the length direction of the horizontal guide rail 11, the transverse graduated scale 12 is arranged along the length direction of the horizontal guide rail 11, and the transverse displacement of the outer lifting rod 13 can be calibrated through the transverse graduated scale 12.

The outer lifting rod 13 is a hollow rod, the inner lifting rod 14 is a solid rod, the inner lifting rod 14 is inserted into the outer lifting rod 13, and the elastic buckle 15 is fixed at the top end of the inner lifting rod 14. The elastic buckle 15 is used for clamping the pendulum bob 6, and the release of the pendulum bob 6 at any position without initial speed is realized. The height adjusting bolt 19 is disposed on the outer wall of the outer rod 13 in a screw-fit manner, and the elastic buckle 15 can stay at a set height position by lifting the inner rod 14 in the outer rod 13 and then screwing the height adjusting bolt 19. The illustrated elastic buckle 15 is formed by two semicircular snap rings, the upper ends of which are provided with an extension part, and the diameter of an inner cavity formed by the two semicircular snap rings is smaller than that of the pendulum bob 6 under the condition that the elastic buckle is not stressed, so that the pendulum bob 6 is firmly clamped on the elastic buckle 15. Under the condition that the two semicircular clamping rings are pulled outwards by holding the extension part, the diameter of an inner cavity formed by the two semicircular clamping rings can be enlarged to be larger than that of the pendulum so as to realize the release of the pendulum 6 without initial speed.

According to the accurate simple pendulum experiment device, the photoelectric door 16 can be driven to lift along with the sliding table 7 by rotating the hand crank 1, the cycloid pendulum 6 at the lowest point position is aligned with the laser hole 27 on the photoelectric door 16 by rotating the rotating wheel 24 on the wire winding seat 18 to wind or release the cycloid 17, then the length of the cycloid 17 is determined by reading the scale on the vertical scale 20, and the requirements of different cycloid length experiments are met. By moving the outer lifting rod 13 on the horizontal guide rail 11 and adjusting the height of the inner lifting rod 14, the pendulum bob 6 can be fixed at any transverse position and any height position, and the release of the pendulum bob 6 without initial speed can be realized by using the elastic buckle 15. The horizontal distance between the initial position of the pendulum bob 6 and the position of the lowest point can be determined by reading the position of the elastic buckle 15 on the transverse graduated scale 12, the pendulum angle can be obtained according to a trigonometric function under the condition that the horizontal distance and the cycloid length are known, the height of the pendulum bob 6 is further determined, and the speed of the pendulum bob 6 passing through the lowest point can be calculated according to energy conservation. By calculating the period of the swing, the local acceleration can be calculated.

Claims

1. An accurate simple pendulum experiment device comprises a base (10), a lead screw (5), a lead screw vertical plate (3), a cycloid (17) and a pendulum bob (6), wherein the lead screw vertical plate is fixed on the base (10), an upper fixing table (2) and a lower fixing table (8) are respectively fixed at the upper end and the lower end of the lead screw vertical plate, the upper end and the lower end of the lead screw are respectively arranged on the upper fixing table and the lower fixing table through bearings, the lead screw (5) is in a vertical state, and a hand crank (1) is fixed at the upper end of the lead screw; the method is characterized in that: a winding seat (18) is fixed on the upper fixing table (2), the cycloid is telescopically arranged on the winding seat, and the pendulum bob is fixed at the lower end of the cycloid; a sliding table (7) is arranged on the screw rod, the sliding table is in transmission fit with the screw rod through a thread pair, a guide rod (4) is fixed on a vertical plate of the screw rod, the length direction of the guide rod is consistent with the length direction of the screw rod, and a guide groove matched with the guide rod is arranged on the sliding table; be fixed with on the slip table and carry out photoelectric door (16) that detect the pendulum through the minimum position moment, set up on the photoelectric door with the laser hole (27) that the minimum position of pendulum aligns, be fixed with on the lead screw riser and carry out the vertical scale (20) of maring to the length of cycloid.

2. The precise simple pendulum experimental apparatus according to claim 1, wherein: the device comprises a transverse pendulum releasing mechanism, wherein the transverse pendulum releasing mechanism consists of a horizontal guide rail (11), a lifting outer rod (14), a lifting inner rod (14) and an elastic buckle (15), the horizontal guide rail is positioned right below a pendulum (6), and the length direction of the horizontal guide rail is consistent with the swinging direction of the pendulum; the outer lifting rod is arranged on the horizontal guide rail (11) through a sliding block, the inner lifting rod is telescopically inserted into the outer lifting rod, and a fixing bolt for positioning the extension length of the inner lifting rod is fixed on the outer lifting rod; a transverse graduated scale (12) for calibrating the horizontal distance between the initial point and the lowest point of the pendulum bob is fixed on the base (10) or the horizontal guide rail (11);

the elastic buckle is fixed at the upper end of the lifting inner rod, and the central point of the elastic buckle, the central point of the pendulum bob at the lowest position and the central line of the horizontal guide rail in the length direction are positioned in the same plane; the elastic buckle is composed of two semicircular clamping rings, an extending part is arranged at the upper end of each semicircular clamping ring, the diameter of an inner cavity formed by the two semicircular clamping rings is smaller than that of the pendulum bob (6) under the condition that the elastic buckle is not stressed, and the diameter of the inner cavity formed by the two semicircular clamping rings can be enlarged to be larger than that of the pendulum bob under the condition that the two semicircular clamping rings are pulled outwards by holding the extending part.

3. The precise simple pendulum experimental apparatus according to claim 1 or 2, wherein: a rotating wheel (34) for winding or releasing the cycloid (17) is arranged on the winding seat (18), a threaded hole with a downward opening is formed in the winding seat, and the cycloid extends out through the threaded hole; a cycloid fixing bolt (25) for fixing the cycloid in the threaded hole is arranged in the threaded hole.

4. The precise simple pendulum experimental apparatus according to claim 1 or 2, wherein: the lead screw vertical plates (3) are fixed on the base (10) through the L-shaped fixing plates (9), the number of the guide rods (4) is two, and the two guide rods are respectively located on two sides of the lead screw (5).