CN210015588U - Projectile motion demonstration instrument - Google Patents

Abstract

In order to quickly and accurately verify the free fall motion law, the mechanical energy conservation law and the throwing motion law, a projectile motion demonstration instrument is provided. The demonstration instrument mainly comprises a pendulum bob, a support rod, a short slide bar, a photoelectric door, a timer, a screw, a semicircular disc, a light spring, a support, a panel, a horizontal baffle and a base. According to the utility model provides a design, can measure the bobble of vertical direction whereabouts instantaneous speed and the whereabouts height of not co-altitude department, verify the law of motion of free fall and the law of conservation of mechanical energy, can draw the roughly movement track of two bobbles, make the student more audio-visual understand the horizontal throw motion of study, combine free fall, the three experiment of mechanical energy conservation and horizontal throw motion on a demonstration appearance, practice thrift the cost, more be favorable to the experiment exploring the development of teaching.

Description

Projectile motion demonstration instrument

Technical Field

The utility model relates to a physical teaching experimental apparatus especially relates to a projectile motion demonstration appearance.

Background

The projectile motion experiment is an important experiment in high school physics teaching, a dotting timer is mostly used for verifying the free falling body motion rule and the mechanical energy conservation law at present, a heavy object drives a paper tape to fall, the friction resistance is large, and the experiment error is also large; when the horizontal projectile motion demonstrator is used for experiments, the elastic metal sheet is knocked by the small hammer, so that the horizontal projectile motion cannot be guaranteed to be knocked by the same force every time, only the horizontal projectile motion can be qualitatively researched, the motion track of an object cannot be drawn, the small ball A cannot be guaranteed to do the horizontal projectile motion by knocking the metal sheet, the small ball A always performs the slightly upward oblique projectile motion, the height cannot be adjusted, only one height set by the instrument can be observed, and the demonstration is not universal.

Disclosure of Invention

In order to overcome above not enough, measure the instantaneous speed of object free fall time in not co-altitude department fast and accurately, judge the kinetic energy and the potential energy change of this point, the orbit of object doing the flat throw motion is drawn, reachs the law of motion of flat throw motion better, the utility model provides a projectile motion demonstration appearance relates to a physical teaching experimental apparatus. The demonstration instrument mainly comprises a pendulum bob, a light bar, a support bar, a short slide bar, a small wood block, a small ball A, a photoelectric door 1, a nut 1, a photoelectric door 2, a timer, a screw, a semicircular disc, a spring frame, a light spring, a small ball B, a support, a panel, drawing paper, carbon paper and white paper, a nut 2, a horizontal baffle, a base, a drawing pin, a level gauge, a screw rod and support legs, and is very convenient to use as a whole. According to the utility model provides a design, the flat throw motion of this demonstration appearance is beaten the iron sheet by original manual and is become to be beaten the short slide bar of pendulum from the fixed altitude release, every time all beats with the same power, changes the baffle height, can experiment many times, also can draw the trace that the bobble was flat throw motion, by the vertical ascending instantaneous speed of bobble of automatic measurement of photogate and time-recorder, become quantitative research by qualitative research, more be favorable to the experiment to explore developing of teaching. The technical problem solved by the utility model is that the scheme mainly has the following points.

1. The pendulum bob is fixed at one end of the light bar, the other end of the light bar is sleeved on a screw at the center of the semicircular disc, the light bar can be fixed or loosened by an adjusting screw, the light bar can rotate around the screw, uniform angle scales are arranged at the edge of the semicircular disc, the lower end of the semicircular disc is fixed at the back of the support through the screw and the support rod, the light spring is installed in the middle of the spring frame, the short slide bar penetrates through a hollow groove in the middle of the spring frame and the support top plate and is hung on the spring frame and can freely slide along the spring frame to freely release the pendulum bob, and the pendulum bob just can be hit on the short slide bar.

2. Photoelectric door 2 fix the base, pellet A under the position department, can not remove, photoelectric door 1 is fixed on horizontal baffle, carbon paper and plain paper are spread on horizontal baffle, drawing paper is fixed on the panel with the drawing pin, a position for the record pellet falls down, carbon paper and plain paper and drawing paper all can be changed at any time, horizontal baffle both ends have the dead slot, fix on the support through nut 1 and nut 2, adjusting nut 1 and nut 2, photoelectric door 1 follows horizontal baffle and can remove about together, also can reciprocate.

3. The panel on be carved with even length scale, the time interval equal department at the free fall is marked with the scale, timer and spirit level are pasted at the base both ends, little billet, spring frame, photogate 2, panel are all fixed and can not be removed on the support, whole demonstration appearance is supported by the supporting legs, have the screw rod on the supporting legs and can adjust the balance of whole demonstration appearance.

4. The small balls A and B are made of opaque materials, have the same specification and have the diameter not more than 1.5 cm.

The utility model has the advantages that the phenomenon that the wood block is knocked by a small wood hammer for the original experiment and is possibly thrown obliquely upwards is changed; the instantaneous speed and the falling height of the small balls falling in the vertical direction at different heights can be measured, and the motion law of the free falling body and the law of conservation of mechanical energy are verified; the general track of the object doing the horizontal projectile motion can be drawn, so that students can understand and learn the horizontal projectile motion more visually, and the rule of the horizontal projectile motion can be obtained through comparison and analysis; three experiments of free falling, mechanical energy conservation and horizontal projectile motion are combined on one demonstration instrument, so that the cost and the placement space of the teaching aid are greatly saved.

Drawings

The present invention will be further explained with reference to the accompanying drawings and examples, wherein fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

The utility model provides a projectile motion demonstration appearance can combine with new experimental scheme and traditional experimental method, verifies freefall motion law, flat projectile motion law and mechanical energy conservation law fast and accurately.

The structure schematic diagram of the utility model is shown in fig. 1, and comprises a pendulum bob (1), a light bar (2), a support bar (3), a short slide bar (4), a small wood block (5), a small ball A (6), a photoelectric door 1 (7), a nut 1 (8), a photoelectric door 2 (9), a timer (10), a screw (11), a semicircular disc (12), a spring frame (13), a light spring (14), a small ball B (15), a bracket (16), a panel (17), drawing paper (18), carbon paper and white paper (19), a nut 2 (20), a horizontal baffle (21), a base (22), a drawing pin (23), a level meter (24), a screw rod (25) and a support leg (26). The pendulum bob (1) is fixed at one end of the light bar (2), the other end of the light bar (2) is sleeved on a screw (11) at the center of a circle of the semicircular disc (12), the light bar (2) can be fixed or loosened by an adjusting screw (11), the light bar (2) can rotate around the screw (11), uniform angle scales are arranged at the edge of the semicircular disc (12), the lower end of the semicircular disc (12) is fixed at the back of the support (16) through the screw and the support rod (3), the light spring (14) is installed in the middle of the spring frame (13), the short slide bar (4) penetrates through a hollow groove in the middle of the spring frame (13) and the top plate of the support (16) and is hung on the spring frame (13), the pendulum bob can freely slide along the spring frame (13), the pendulum bob (1) is freely released, and the pendulum bob (1) can just hit the short slide bar (; the photoelectric door 2 (9) is fixed at the position right below the base (22) and the small ball A (6) and cannot move, the photoelectric door 1 (7) is fixed on a horizontal baffle plate (21), the carbon paper and the white paper (19) are paved on the horizontal baffle plate (21), the drawing paper (18) is fixed on a panel (17) by a drawing pin (23) and is used for recording the falling position of the small ball, the carbon paper, the white paper (19) and the drawing paper (18) can be replaced at any time, both ends of the horizontal baffle plate (21) are provided with empty slots and are fixed on a bracket (16) by a nut 1 (8) and a nut 2 (20), the photoelectric door 1 (7) can move left and right along with the horizontal baffle plate (21) and can also move up and down, the panel (17) is provided with uniform length scales, and scales are marked at equal time intervals of free falling bodies, the timer (10) and the level meter (24) are adhered to two ends of the base (22), the small wood block (5), the spring frame (13), the photoelectric door (2), (9) and the panel (17) are all fixed on the bracket (16) and cannot move, the whole demonstration instrument is supported by supporting legs (26), and the supporting legs (26) are provided with screws (25) which can adjust the balance of the whole demonstration instrument; the small ball A (6) and the small ball B (15) are made of opaque materials, have the same specification and have the diameter not more than 1.5 cm.

In this embodiment, the screws (25) on the two support legs (26) are first adjusted to center the bubble in the level (24) and balance the entire presenter.

And (5) verifying the law of motion of the free falling body and the law of conservation of mechanical energy. The small ball A (6) is placed between the small wood block (5) and the short sliding rod (4), the small ball A (6) cannot fall under the action of the elastic force of the light spring (14), the nut 1 (8) and the nut 2 (20) are adjusted, the horizontal baffle (21) is moved, the small ball A (6) is enabled to be over against the photoelectric door 1 (7), and the small ball A (6) can smoothly pass through the centers of the photoelectric door 1 (7) and the photoelectric door 2 (9) when falling. Switching on a timer (10) and a photoelectric gate circuit, pulling a pendulum bob (1) to a fixed scale (aligning the scale with a light bar (2)) and releasing the pendulum bob from rest, impacting a short slide bar (4) to enable a small ball A (6) to do free-falling movement, recording the instantaneous speed and interval time of the small ball A (6) passing through the photoelectric gate (1) (7) and the photoelectric gate (2) (9) and the height of a baffle, changing the height of the baffle, and carrying out multiple experiments; the ball A (6) is changed into balls with different materials and different masses, the operations are repeated at the same baffle height, the instantaneous speed and the interval time of the ball passing through the photoelectric gates 1 (7) and 2 (9) and the variation of the speed are compared, and the free falling body motion law and the mechanical energy conservation law (the ball rotation is not considered in the middle school stage) can be verified through comparison and calculation.

And (5) verifying the flat projectile motion law. The small ball A (6) is placed between the small wood block (5) and the short slide bar (4), the small ball B (15) is placed at the L-shaped bent part of the short slide bar (4), the nut 1 (8) and the nut 2 (20) are adjusted, the horizontal baffle (21) is moved, the photoelectric door 1 (7) is positioned at the lower left of the small ball A (6), and the small ball A (6) can be smoothly beaten on the horizontal baffle (21) when falling. The timer (10) and the photoelectric gate circuit are closed, the pendulum bob (1) is pulled to a fixed scale (the scale is aligned with the light rod (2)) and is released from the rest, the short slide rod (4) is impacted, the small ball A (6) makes free falling body motion, the small ball B (15) makes flat throw motion, the sound of the small ball A (6) and the small ball B (15) hitting the horizontal baffle (21) is carefully heard (only one sound is produced when the two balls fall down), whether the two small balls fall to the ground or not is judged, marks left by carbon paper and white paper (19) are hit according to the two balls, a pen is used for correspondingly tracing points on the drawing paper (18), the height of the baffle is recorded, the height of the baffle is changed (the height is changed according to the marked scale, the rule is conveniently found out, the traced points are connected by a smooth curve for multiple times of experiments, the approximate motion tracks of the two small balls can be drawn, and the rule of the flat throw motion can be obtained through comparison and analysis.

Claims (4)

1. A projectile motion demonstration instrument mainly comprises a pendulum bob, a light bar, a support bar, a short slide bar, a small wood block, a small ball A, a photoelectric door 1, a nut 1, a photoelectric door 2, a timer, a screw, a semi-circular disc, a spring frame, a light spring, a small ball B, a support, a panel, drawing paper, carbon paper and white paper, a nut 2, a horizontal baffle, a base, a drawing pin, a level, a screw rod and a support leg, and is characterized in that the pendulum bob is fixed at one end of the light bar, the other end of the light bar is sleeved on the screw at the center of the semi-circular disc, an adjusting screw can fix or loosen the light bar, the light bar can rotate around the screw, the edge of the semi-circular disc is provided with uniform angle scales, the lower end of the semi-circular disc is fixed at the back of the support through the screw and the support bar, the light spring is arranged in the middle of the spring frame, the short slide bar passes through a hollow groove in, the pendulum bob can freely slide along the spring frame and freely release, and the pendulum bob just can hit the short slide bar.

2. The projectile motion demonstration instrument according to claim 1, wherein the photoelectric door 2 is fixed at a position under the base and the ball a and cannot move, the photoelectric door 1 is fixed on a horizontal baffle, carbon paper and white paper are laid on the horizontal baffle, drawing paper is fixed on a panel through drawing pins and used for recording the falling position of the ball, the carbon paper, the white paper and the drawing paper can be replaced at any time, two ends of the horizontal baffle are provided with empty slots, the horizontal baffle is fixed on a bracket through the nut 1 and the nut 2, the nut 1 and the nut 2 are adjusted, and the photoelectric door 1 can move left and right along with the horizontal baffle and can also move up and down.

3. The projectile motion demonstrator of claim 1, wherein the panel is marked with uniform length scales, the scales are marked at equal intervals of free fall, the timer and the level gauge are adhered to two ends of the base, the small wood block, the spring frame, the photoelectric door 2 and the panel are all fixed on the support and cannot move, the whole demonstrator is supported by the support legs, and the support legs are provided with screws for adjusting the balance of the whole demonstrator.

4. The projectile motion demonstrator of claim 1, wherein said pellet a and said pellet B are opaque and have the same dimensions and a diameter of no more than 1.5 cm.