A free fall and flat projectile object landing comparison experiment device

Abstract

The application discloses a free fall and horizontal projectile object simultaneous landing contrast experiment device, which comprises a vertical installation support (2) on a base (1), the support (2) is a three-section telescopic round pole piece, a rotating shaft (7) is fixedly installed on the middle section, a metal rod (6) is installed on the rotating shaft (7), a lower plate (4) is installed at the lower end of the support (2), and an upper plate (8) is installed at the upper end of the support (2), the upper end (23) of the metal rod (6) is clamped with a contrast ball (10) in the upper plate long hole (12), the lower end (24) of the metal rod (6) is clamped with an A ball (5) in the lower plate long hole (17), the lower end (24) is hooked and positioned through a trigger device, and the B ball (11) is placed on the circular-arc-shaped recess (16) of the lower plate (4). The device adopts a third ball contrast method to carry out experimental research, weakens the influence of the small ball hitting the ground twice, and clearly and explicitly verifies the physical law of the free fall and the horizontal projectile object simultaneous landing.

Description

TECHNICAL FIELD

[0001] The present application relates to a physical experiment device, in particular to a contrast experiment device of free fall and simultaneous landing of a projectile. BACKGROUND

[0002] In the Newtonian mechanics system, the projectile motion can be decomposed into two motions by using the Galileo transformation: uniform linear motion along the horizontal direction and uniformly accelerated falling motion along the vertical direction. The combination of the two motions is the projectile motion. In the vertical direction, the projectile motion has no initial velocity, so the motion of the projectile in the vertical direction is the same as the free fall of the object.

[0003] However, in teaching, students always cannot understand, for example, two objects are the same, one is a projectile falling, and one is a vertical falling, the starting points are the same, but the motion distances of the two objects are different. The trajectory of the projectile falling object is a parabola, and does the projectile falling object really land at the same time as the free falling object? Therefore, in teaching, various experimental methods are used to prove that the objects falling from the same height, whether falling vertically or falling along the horizontal direction, reach the ground at the same time. Generally, in order to enable students to intuitively see or feel this conclusion, a mechanical method is used to make two identical small balls move at the same time, one free falling and the other projectile motion, and the sound of the two small balls landing at the same time is heard. Due to the limited accuracy of the mechanical structure and the influence of air resistance, the probability of the two small balls landing at the same time and hearing the sound of the impact with the ground at the same time is extremely low. Although the time interval of the two balls falling to the ground is very short, the "two impact" sounds of the two balls falling to the ground can generally be distinguished. Students do not have the approximate concept of engineering practice, and think that the "two impact" sound is the conclusion that the "free falling body and the projectile body land at the same time" is incorrect. Therefore, these experiments seriously affect the teaching effect. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings in the background art, and to verify that the falling time of the projectile motion object is only related to the height of the starting point by using a more accurate device to verify that the free falling body and the projectile body land at the same time. At the same time, a third ball is used for contrast experiment, and the influence of the two impacts of the small balls is weakened. That is, compared with the last landing sound of the third ball, the two impact sounds of the two small balls with a very short time interval before are blurred as the same sound, or slightly different, which can be easily understood as being within the error allowed range, and not as the conclusion that the "free falling body and the projectile body land at the same time" is incorrect.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] The free falling body and the projectile body land at the same time contrast experiment device of the present application, like Figure 1As shown, including the base 1, support 2, locking screw 3, lower plate 4, A ball 5, metal rod 6, shaft 7, upper plate 8, spring 9, contrast ball 10, B ball 11, trigger device 25.

[0007] The base 1 is vertically installed on the support 2, the support 2 is a three-section telescopic round rod, the middle section is fixedly installed with the shaft 7, and the shaft 7 is installed with the metal rod 6.

[0008] The metal rod 6 is a hollow rigid rod with a circular cross section, and the metal rod 6 is connected with the shaft 7 at the middle symmetric position and can rotate freely around the shaft 7. The upper and lower ends of the metal rod 6 are made into square cross-section rods, the square cross-section rod on the upper side of the metal rod 6 is the upper end 23, and the square cross-section rod on the lower side of the metal rod 6 is the lower end 24. When the upper end of the metal rod 6 is inclined to the left by an angle of 20-30 degrees, the side surface of the square cross-section rod is perpendicular to the ground.

[0009] The lower end of the support 2 is installed with the lower plate 4, and the upper end is installed with the upper plate 8, and is fixed with the locking screw 3.

[0010] The upper plate 8 is as Figure 4 shown, the right rear protruding part is provided with an upper plate mounting hole 13 matched with the support 2, the right end upper side is provided with a protrusion 14, and the left side of the protrusion 14 is provided with an upper plate long hole 12 along the length direction.

[0011] The lower plate 4 is a double-folded plate as Figure 5 shown, the left side rear part of the lower plate is provided with a lower plate mounting hole 15 matched with the support 2, the upper surface of the upper plate is provided with a circular arc-shaped groove 16 along the length direction, the right end is provided with a rectangular protrusion 18, and the left side of the protrusion 18 is provided with a lower plate long hole 17.

[0012] The lower plate 4 is provided with a trigger device 25 at the bottom of the upper plate.

[0013] When the metal rod 6 is installed, the upper end 23 is inserted into the upper plate long hole 12 of the upper plate 8, one end of the spring 9 is fixed on the protrusion 14, and the other end pulls the upper end 23 to the right side.

[0014] The lower end 24 of the metal rod 6 is inserted into the lower plate long hole 17 of the lower plate 4, and the lower end 24 is hooked and positioned by the trigger device. At this time, the protrusion 18 on the right side of the lower plate 4 cooperates with the right side surface of the lower end 24 to clamp the A ball 5, and the left side surface of the upper end 23 clamps the contrast ball 10 in the upper plate long hole 12.

[0015] The B ball 11 is placed on the circular arc-shaped groove 16 of the lower plate 4.

[0016] The trigger device 25 includes the front hook spring sheet 19, the front end of the spring sheet 19 is retracted to form a gap, the A ball 5 falls from the lower plate long hole 17 and passes through the gap without scratching the spring sheet 19, the front end of the spring sheet 19 is provided with a button 21, the middle part of the spring sheet 19 is provided with a long strip-shaped adjusting hole 22 along the length direction, the adjusting screw 20 passes through the adjusting hole 22 and can slide in the adjusting hole 22, and the adjusting screw 20 is used for fixing the trigger device 25.

[0017] The base 1 is a cross-shaped seat body made of metal, a convex metal cylinder is arranged in the middle of the seat body, the cylinder inner hole is inserted into the support 2, and threaded holes are arranged on four extending ends of the cross-shaped seat body, and the foot screws 26 are arranged on the threaded holes to adjust the verticality of the support 2.

[0018] The A ball 5, the B ball 11 and the contrast ball 10 are made of the same kind of light metal material and have the same diameter.

[0019] As can be seen from the technical scheme provided by the above-mentioned application, the beneficial effects of the free-fall and flat-throw object simultaneous landing comparison experiment device provided by the application are as follows: a precise device is provided to verify that the free-fall and flat-throw object land at the same time, and a third ball comparison method is used for experimental research to weaken the influence of the two times of ball impact, that is, the sound of the two times of ball impact on the ground is blurred as the same sound or slightly different, which can be easily understood as being within the error allowable range and not being incorrect in the conclusion that the free-fall and flat-throw object land at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and are used to explain the application, and do not constitute a limitation on the application. In the drawings:

[0021] Figure 1 It is a structure schematic view of the free-fall and flat-throw object simultaneous landing comparison experiment device.

[0022] Figure 2 It is a left view of the free-fall and flat-throw object simultaneous landing comparison experiment device.

[0023] Figure 3 It is a schematic view of the experimental state of the free-fall and flat-throw object simultaneous landing comparison experiment device without the contrast ball.

[0024] Figure 4 It is a schematic view of the upper plate structure of the free-fall and flat-throw object simultaneous landing comparison experiment device.

[0025] Figure 5It is a free-fall and flat projectile object landing simultaneously comparative experiment device lower plate structure schematic view of the present application.

[0026] Figure 6 It is a free-fall and flat projectile object landing simultaneously comparative experiment device trigger device structure schematic view of the present application.

[0027] Figure 7 It is a free-fall and flat projectile object landing simultaneously comparative experiment device base structure schematic view of the present application.

[0028] In the figure: 1, base, 2, support, 3, locking screw, 4, lower plate, 5, A ball, 6, metal rod, 7, rotating shaft, 8, upper plate, 9, spring, 10, comparison ball, 11, B ball, 12, upper plate long hole, 13, upper plate mounting hole, 14, protruding block, 15, lower plate mounting hole, 16, groove, 17, lower plate long hole, 18, protrusion, 19, spring piece, 20, adjusting screw, 21, button, 22, adjusting hole, 23, upper end, 24, lower end, 25, trigger device, 26, foot screw. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0030] The embodiments of the present application will be further described below with reference to the drawings.

[0031] A free-fall and flat projectile object landing simultaneously comparative experiment device of the present application, as shown in Figure 1 The device includes a base 1, a support 2, a locking screw 3, a lower plate 4, an A ball 5, a metal rod 6, a rotating shaft 7, an upper plate 8, a spring 9, a comparison ball 10, a B ball 11, an upper end rod 23, a lower end rod 24, and a trigger device 25.

[0032] The support 2 is vertically installed on the base 1, and is a three-section telescopic round rod for convenience of operation. The rotating shaft 7 is fixedly installed in the middle section of the middle section, and the metal rod 6 is installed on the rotating shaft 7.

[0033] The metal rod 6 is a hollow rigid rod with circular cross section, which can reduce the weight of the rod and avoid bending or elastic deformation of the rod during operation. The metal rod 6 is connected to the rotating shaft 7 at the middle symmetrical position and can rotate freely around the rotating shaft 7. The upper and lower ends of the metal rod 6 are made into square cross section rods. The square cross section rod on the upper side of the metal rod 6 is the upper end 23, and the square cross section rod on the lower side of the metal rod 6 is the lower end 24. In order to facilitate the metal rod 6 to hold the small ball and ensure that the small ball does not collide and rub during movement, when the upper end of the metal rod 6 is inclined to the left by an angle of 20-30 degrees, the side surface of the square cross section rod is perpendicular to the ground.

[0034] The lower end of the support 2 is installed with the lower plate 4, and the upper end is installed with the upper plate 8, which are fixed by lock screws 3. The upper plate 8 is shown in Figure 4 the right rear protruding part, and the right upper end is provided with a protrusion 14. The left side of the protrusion 14 is provided with an upper plate long hole 12 along the length direction.

[0035] The lower plate 4 is a double folding plate as shown in Figure 5 The left side of the lower folding plate is provided with a lower plate mounting hole 15 for the support 2. The upper surface of the upper folding plate is provided with a circular arc shaped groove 16 along the length direction. The right end is provided with a rectangular protrusion 18, and the left side of the protrusion 18 is provided with a lower plate long hole 17. The trigger device 25 is installed at the bottom of the upper folding plate of the lower plate 4. The groove 16 can ensure that the A ball 5 can be placed stably on the groove 16, and the A ball 5 is placed on the upper folding plate, so that when the A ball 5 does the horizontal throwing motion, the small ball will not collide with the lower folding plate.

[0036] When the metal rod 6 is installed, the upper end 23 is inserted into the upper plate long hole 12 of the upper plate 8. One end of the spring 9 is fixed on the protrusion 14, and the upper end 23 is pulled to the right side. The lower end 24 of the metal rod 6 is inserted into the lower plate long hole 17 of the lower plate 4, and the lower end 24 is hooked and positioned by the trigger device. At this time, the protrusion 18 on the right side of the lower plate 4 cooperates with the right side of the lower end 24 to hold the A ball 5, and the left side of the upper end 23 can hold the contrast ball 10 in the upper plate long hole 12.

[0037] The triggering device 25 is the fixing and firing mechanism of the entire device. It includes a spring plate 19 with a hook at the front. The outer front end of the spring plate 19 retracts to form a notch. When ball A 5 falls from the elongated hole 17 in the lower plate, it passes through the notch without scraping against the spring plate 19. The inner front end of the spring plate 19 has a button 21. The middle of the spring plate 19 has an elongated adjustment hole 22 along its length. The adjustment screw 20 passes through the adjustment hole 22 and can slide within the adjustment hole 22, and is used to fix the triggering device 25. Because this device needs to simultaneously hold the comparison ball 10 and ball A 5 and ensure that the two balls fall at the same time, the tilt angle of the metal rod 6 when balanced must be adjusted according to the size of the balls. That is, according to the diameter of the two small balls, after loosening the adjustment screw 20, the spring plate 19 moves back and forth so that when the front end of the spring plate hooks the lower end 24, the upper end 23 of the metal rod can hold the comparison ball 10, and the lower end 24 can hold the ball A 5.

[0038] To ensure stable operation of the device, the base 1 is made of metal in the shape of a cross, with a raised metal cylinder in the middle. The inner hole of the cylinder is into which the bracket 2 is inserted. The four protruding ends of the cross-shaped base have threaded holes on which anchor screws 26 are installed. It should be noted that the protruding ends of the cross-shaped base should not be too wide, so as not to affect the vertical landing of ball A 5.

[0039] Ball A (5), Ball B (11), and Comparison Ball 10 are all made of the same type of lightweight metal material and have the same diameter.

[0040] Operation process:

[0041] 1. First press Figure 1 After connecting the device as shown, adjust the bracket 2 to be perpendicular to the ground by using the anchor screw 26. Then, according to the diameter of ball A 5, ball B 11 and comparison ball 10, loosen the adjusting screw 20 and move the spring plate 19 back and forth so that when the front end of the spring plate 19 hooks the lower end 24, the upper end 23 of the metal rod can hold the comparison ball 10 and the lower end 24 can hold ball A 5. At this time, the angle between the metal rod 6 and the vertical direction is between 20 and 30 degrees.

[0042] 2. Place ball A 5 on the arc-shaped groove 16 of the lower plate 4. At this time, the ground should be flat and made of the same material to facilitate judging the order of the sound of the balls hitting the ground.

[0043] 3. Press button 21, and the lower end 24 will be released from the restraint of spring plate 19. Spring 9 will quickly pull the upper end 23 of metal rod 6 to rotate to the right, causing ball 10 to fall. At the same time, ball A 5 falls, and the lower end 24 hits ball B 11, causing it to produce projectile motion, that is, the three balls start moving at the same time.

[0044] 4. Determine the order of the ball falling to the ground, experiments show that: compared with the clear time interval of the last landing of the contrast ball 10, the sound of the A ball 5 and the B ball 11 hitting the ground is blurred, and due to the contrast effect of the last landing of the contrast ball 10, the students will identify the sound of the A ball 5 and the B ball 11 hitting the ground as the same sound, thereby verifying the conclusion that the free falling body and the projectile object land at the same time. The existence of the contrast ball 10 weakens the small difference in the landing time of the A ball 5 and the B ball 11, and the last landing of the contrast ball further confirms that the landing time of the projectile motion of the object and the free falling object is only related to the height of the starting point.

[0045] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An experimental apparatus for comparing the simultaneous landing of free-falling and projectile objects, characterized in that, Includes base (1), bracket (2), locking screw (3), lower plate (4), A ball (5), metal rod (6), rotating shaft (7), upper plate (8), spring (9), comparison ball (10), B ball (11) triggering device (25); A bracket (2) is vertically installed on the base (1). The bracket (2) is a three-section telescopic round rod. A rotating shaft (7) is fixedly installed on the middle section. A metal rod (6) is installed on the rotating shaft (7). The metal rod (6) is a hollow rigid rod with a circular cross section. The metal rod (6) is connected to the rotating shaft (7) at a symmetrical position in the middle and can rotate freely around the rotating shaft (7). Both the upper and lower ends of the metal rod (6) are made into square cross section rods. The square cross section rod located on the upper side of the metal rod (6) is the upper end (23), and the square cross section rod located on the lower side of the metal rod (6) is the lower end (24). When the upper end of the metal rod (6) is tilted to the left at an angle of 20-30 degrees, the side of the square cross section rod is perpendicular to the ground. The bracket (2) has a lower plate (4) installed at the lower end and an upper plate (8) installed at the upper end, and is fixed with locking screws (3) respectively. The upper plate (8) has a protruding part on the right rear side with an upper plate mounting hole (13) for connecting with the bracket (2), and a protrusion (14) on the upper right end. The protrusion (14) has an upper plate elongated hole (12) on the left side along the length direction. The lower plate (4) is a double-folded plate. The lower plate has a lower plate mounting hole (15) for connecting with the bracket (2) on the left rear side. The upper plate has an arc-shaped groove (16) along the length direction on the upper surface. The right end has a rectangular protrusion (18). The protrusion (18) has a lower plate elongated hole (17) on the left side. A triggering device (25) is installed at the bottom of the upper folding plate of the lower plate (4); When the metal rod (6) is installed, the upper end (23) is inserted into the upper plate long hole (12) of the upper plate (8), one end of the spring (9) is fixed on the protrusion (14), and the other end pulls the upper end (23) to the right; the lower end (24) of the metal rod (6) is inserted into the lower plate long hole (17) of the lower plate (4), and the lower end (24) is hooked and positioned by the triggering device. At this time, the protrusion (18) on the right side of the lower plate (4) cooperates with the right side of the lower end (24) to hold the A ball (5), and the left side of the upper end (23) holds the comparison ball (10) in the upper plate long hole (12); A ball B (11) is placed on the arc-shaped groove (16) of the lower plate (4).

2. The experimental apparatus for comparing the simultaneous landing of free-fall and projectile objects as described in claim 1, characterized in that, The triggering device (25) includes a spring plate (19) with a hook at the front end. The outer side of the front end of the spring plate (19) retracts to form a notch. When ball A (5) falls from the long hole (17) in the lower plate, it passes through the notch and will not scrape against the spring plate (19). The inner side of the front end of the spring plate (19) has a button (21). The middle part of the spring plate (19) has a long strip-shaped adjustment hole (22) along the length direction. The adjustment screw (20) passes through the adjustment hole (22) and can slide in the adjustment hole (22) and is used to fix the triggering device (25).

3. The experimental apparatus for comparing the simultaneous landing of free-fall and projectile objects according to claim 1, characterized in that, The base (1) is a metal cross-shaped seat with a protruding metal cylinder in the middle. The inner hole of the cylinder is inserted into the bracket (2). The four protruding ends of the cross-shaped seat have threaded holes, and anchor screws (26) are installed on them.

4. The experimental apparatus for comparing the simultaneous landing of free-fall and projectile objects according to claim 1, characterized in that, The A ball (5), B ball (11) and the comparison ball (10) are all made of the same type of light metal material and have the same diameter.

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