CN202331997U - Energy conservation demonstrator - Google Patents

Abstract

Disclosed is an energy conservation demonstrator. A rotating shaft 2 is fixed on a vertical wood board 1 which is connected with a light oscillating rod 3 capable of freely swaying, a short right angle hook is arranged at the lower end of the oscillating rod, a metal ball 5 with a central hole is hung on the right angle hook, and the mass of the oscillating rod 3 is far less than that of the metal ball 5. A fixing pin 4 is mounted on a vertical board right below the rotating shaft 2, and the distance between the fixing pin and the rotating shaft 2 is slightly shorter than the length of the oscillating rod 3. The right side of the vertical wood board 1 is connected with a horizontal plate 7 on which a piece of white paper 6 (a piece of carbon paper is laid under the white paper) is covered, and a calibrating ruler 8 is installed in front of the horizontal plate. The demonstrator as a whole guarantees that a line on which the rotating shaft and the fixing pin locate is perpendicular to the horizontal plate 7. The metal ball is pulled to a certain height which is h higher than the lowest position, the metal ball is released after being still, and the metal ball and the oscillating rod swing downwards freely around the rotating shaft 2 only under the gravity action. Only the gravity acts during downward swinging, and total mechanical energy is conservative.

Description

The energy conservation demonstration device

Technical field

The utility model relates to a kind of physics facility and experimental technique, is used for the experimental study of verifying energy conservation.

Background technology

The law of conservation of mechanical energy is the philosophy in the dynamics, and promptly any object system is zero like no external force acting or external force acting sum, and when having only conservative force (seeing potential energy) acting in the system again, then the mechanical energy of system (kinetic energy and potential energy sum) remains unchanged.The external force acting is zero, shows the not input mechanical work from the external world; Have only the conservative force acting, promptly have only the conversion of kinetic energy and potential energy, be not converted into other abilities and there is mechanical energy, the conservation of mechanical energy that meets this two condition is all set up all inertial reference systems.The simplification saying of this law is: when particle (or system of particles) moves in potential field, its function and potential energy with remain unchanged; Or kinetic energy and potential energy sum are constant when claiming that object moves in gravity field.

" checking conservation of mechanical energy " is the emphasis experiment of senior high school period; In the general experimental technique, all will use equipment such as spark timer, paper tape, power supply, and operation is difficult; Be difficult to the accuracy that guarantees that spark timer is got ready, make the experimental result error very big.

The simple material of the utility model utilization is processed law of conservation of mechanical energy confirmatory experiment device, accomplishes above-mentioned experiment easily.

The utility model content

The purpose of the utility model provides a kind of verifying energy conservation demonstrating experiment device and experimental technique, physical significance clear and definite.

The purpose of the utility model is achieved in that and adopts device shown in Figure 1; Fixed bias circuit 2 on the wooden riser 1; Connect the lightweight swing arm 3 that can freely swing on the rotation axis; The swing arm lower end has a short right angle hook, metal ball 5 of suspension on the right angle hook with center pit, and guarantee the quality of the quality of swing arm 3 much smaller than metal ball 5.One fixed pin 4 is installed on riser under the rotation axis 2, and the distance of fixed pin and rotation axis 2 is slightly less than the length of swing arm 3.Connect a leveling board 7 on riser 1 right side, be covered with blank sheet of paper 6 (below blank sheet of paper, being lined with transfer paper) on it, at installed in front one rule 8 of leveling board.Device will guarantee that on the whole rotation axis is vertical with leveling board 7 with the straight line at fixed pin place.

Description of drawings

Fig. 1 is checking centripetal force experimental provision and experimental technique structural representation;

1, riser, 2, rotation axis, 3, swing arm, 4, fixed pin, 5, metal ball, 6, blank sheet of paper (pad transfer paper), 7, leveling board, 8, rule.

Embodiment

At first by shown in Figure 1 energy conservation demonstration device each several part is connected, guarantee that the lightweight swing arm does not have friction and freely swings, metal ball 5 hangs on the right angle hook below the swing arm, on leveling board 7, spreads transfer paper along its length, covers with blank sheet of paper above.

As shown in Figure 1, move metal ball to certain altitude---exceed h than extreme lower position, let go after static, this moment only under action of gravity, metal ball and the swing arm moving axis 2 free bottoms that rotate together.In the bottom process, gravity acting is only arranged, total conservation of mechanical energy.

Because when putting the equilibrium position, the kinetic energy of lightweight swing arm is to be transformed by its original potential energy that has basically, the quality of adding swing arm is compared very little with the metal ball quality, so the mechanical energy of metal ball is approximate conservation.If the quality of metal ball is m, be v in the speed of minimum point, then the law of conservation of mechanical energy can be expressed as

$\frac{1}{2}{\mathrm{mv}}^2=\mathrm{mgh}$

When metal ball moved to minimum point by peak, fixed pin 4 had blocked the lightweight swing arm, and metal ball just flies out along horizontal direction.Because the friction force between swing arm and the metal ball is also very little, the speed that metal ball breaks away from swing arm also is approximately equal to v.Metal ball is done level throw motion later on, drops at last on the leveling board 7, be placed with the blank sheet of paper that is covered with transfer paper on the leveling board, thereby metal ball is left a trace at the drop point place.If the metal ball height of drop be H (by metal ball on swing arm extreme lower position to the vertical range on leveling board surface), the distance of metal ball horizontal flight is S (being read by rule 8), just can draw the flat initial velocity of throwing does

$v=S\sqrt{\frac{g}{2H}}$

With formula before the following formula substitution, can obtain

h＝S ²/4H

So in each the measurement, as long as record h, S, three parameters of H respectively, the checking following formula is set up, and has just confirmed law of conservation of mechanical energy establishment.

Note in the experiment, must make right angle hook and metal ball endoporus on the swing arm smooth, reduce friction.

Claims (2)

1. energy conservation demonstration device; It is characterized in that: wooden riser (1) is gone up fixed bias circuit (2); Connect the lightweight swing arm (3) that can freely swing on the rotation axis; The swing arm lower end has a short right angle hook, metal ball (5) of suspension on the right angle hook with center pit, and the quality of swing arm (3) is much smaller than the quality of metal ball (5).

2. energy conservation demonstration device according to claim 1 is installed a fixed pin (4) on riser under the rotation axis (2), the distance of fixed pin (4) and rotation axis (2) is slightly less than the length of swing arm (3); Connect a leveling board (7) on riser (1) right side, be covered with blank sheet of paper (6) on it, below blank sheet of paper, be lined with transfer paper, at installed in front one rule (8) of leveling board, rotation axis is vertical with leveling board (7) with the straight line at fixed pin place.