CN202331999U - Freely-falling body demonstrator - Google Patents

Abstract

The utility model discloses a freely-falling body demonstrator. An n-shaped support is fixed on an insulating base; the support is made of organic glass; an electromagnet is fixed on the upper part of the n-shaped support; the on and off of the electromagnet are controlled by a power supply; when the electromagnet is powered on, a metal ball is attracted, and at the moment that the electromagnet is powered off, the metal ball falls freely; copper wire nets are installed on the inner sides of a left upright plate and a right upright plate of the n-shaped support; and a piece of white paper which has the same size as the copper wire net is covered on one of the left upright plate and the right upright plate of the n-shaped support. During an experiment, a switch of a high voltage generator is switched on to output a high voltage of about 50Kv first and then the switch of the electromagnet is switched off; the metal ball falls freely, and in the falling route of the metal ball, the high voltage generator generate a high voltage once every 0.02 seconds; and the metal ball and the two metal nets generate an electrospark discharge, so that the white paper on the right upright plate is broken down by the electrospark, and thus black dots are left on the white paper, which are similar to position graphs of the ball obtained by a stroboscopic photography at the flashing moment.

Description

A kind of freely falling body demonstration device

Technical field

The utility model relates to a kind of physics facility and experimental technique, is used for a kind of experimental study of freely falling body demonstration.

Background technology

Do not receive any resistance, only under action of gravity and the object that lands is " freely falling body ".Like the object that under the terrestrial gravitation effect, begins to fall by stationary state.Near the earth surface the sky can be regarded constant gravity field as.As do not consider atmospherical drag, the movement of falling object in this zone is a uniformly accelrated rectilinear motion.Its acceleration is constantly equal to gravity acceleration g.Though the gravitation of the earth and object square are inversely proportional to earth centre distance, the radius of the earth much larger than freely falling body the distance of process, so that gravitation can be regarded as near ground is constant, the acceleration of freely falling body promptly is a constant constant.It is that initial velocity is zero uniformly accelrated rectilinear motion.

The checking movement of falling object is that initial velocity is zero uniformly accelrated rectilinear motion; A lot of methods are arranged in practice, as utilize the dotted timer method: let bead drive the paper tape free-falling, on paper tape, lay a little through dotted timer; On paper tape, put on S1, S2, S3, S4 etc. in consecutive identical time then; Calculate and whether satisfy S2-S1=S3-S2=S4-S3,, can verify by falling it is that initial velocity is zero uniformly accelrated rectilinear motion if satisfy; This method major defect is that paper tape frictional resistance is big, measures inaccurate.Also have stroboscopic photography, need more equipment on the classroom, directly to demonstrate, cost is high, is unfavorable for that the student takes action on one's own to operate, and closely experiences.

The simple material of the utility model utilization and than conventional equipment is processed the freely falling body demonstration device, accomplishes above-mentioned experiment easily.

The utility model content

The purpose of the utility model provides a kind of freely falling body apparatus for demonstrating 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 that be fixed with " ∏ " shape support 2 on the insulator foot 1, support is processed with organic glass.At the top fixed electromagnet 5 of " ∏ " shape support, through power supply its energising of control and outage, electromagnet holds metal ball 6 during energising, outage moment metal ball 6 free-fallings.Left and right riser at " ∏ " shape support is inboard, and copper mesh 3 (like Fig. 2) is installed, the blank sheet of paper 7 of one of covering and the same size of copper mesh on a side (like the right side) copper mesh of " ∏ " shape support riser.Single unit system will guarantee that " ∏ " shape support is vertical with base, and left and right two risers are parallel to each other, can not collide vertical drop with both sides during with the free-falling of assurance metal ball.

Organic glass support 2 is wide 20 millimeters, and is high 160 millimeters, about 3 millimeters of thickness.

Copper mesh 3 is suitable with blank sheet of paper 7 sizes, and undersized is in organic glass support 2.

Description of drawings

Fig. 1 is the experimental provision and the experimental technique structural representation of demonstration freely falling body;

1, insulator foot, 2, the organic glass support, 3, copper mesh, 4, power-line terminal, 5, electromagnet, 6, metal ball, 7, blank sheet of paper.

Fig. 2 is the metal copper mesh.Fig. 3 is the blank sheet of paper that is printed on scale label.

Embodiment

By shown in Figure 1 freely falling body lecture experiment device is installed; Copper mesh is vertically smooth; The assurance metal ball can not have the scraping free-falling, and electromagnet power supply is used the J2444 type with J1202 type student power supply, electromagnet, and high pressure generator is used the J1206 type; Can whenever produce a sub-high pressure at a distance from 0.02 second, high voltage is added on the left and right copper mesh.

As shown in Figure 1, during experiment, at first connect the high pressure generator switch; Regulate high pressure generator and make it export about 50 kilovolts high voltage, break off electro-magnet switch again, the metal ball free-falling after stablizing; On the path of metal ball free-falling, whenever produce a sub-high pressure at a distance from 0.02 second high pressure generator, produce a spark discharge through metal ball and two wire nettings; Make that covering the right blank sheet of paper of surveying on the riser is punctured by electric spark, thereby on blank sheet of paper, stay stain one by one, promptly metal ball is in the position at the instantaneous place of discharge; Similar with bead that stroboscopic photography obtains at the instantaneous residing location graphic of flash of light, after the outage, take out and be fixed on the blank sheet of paper on the right panel; With the methods analyst data of handling paper tape, as shown in Figure 3, can verify whether the movement of falling object is that initial velocity is zero uniformly accelrated rectilinear motion.

This instrument has following advantage:

(1) eliminated the frictional influence that produces when testing, reduced the influence of air resistance, measured accurately with the dotted timer method;

(2) simple to operate, can be on the classroom direct lecture experiment, student's operation of taking action on one's own helps teaching.

(3) compare with stroboscopic photography, cost is low, and the economically less developed region also can be realized.

Claims (1)

1. a freely falling body demonstration device is characterized in that: be fixed with " ∏ " shape organic glass support (2) on the insulator foot (1), at the top fixed electromagnet (5) of " ∏ " shape support; Left and right riser at " ∏ " shape support is inboard, and copper mesh (3) is installed, and goes up the blank sheet of paper (7) of one of covering and the same size of copper mesh at a side copper mesh (3) of " ∏ " shape support riser; " ∏ " shape organic glass support single unit system is vertical with base (1), and left and right two risers are parallel to each other; Organic glass support (2) is wide 20 millimeters, and is high 160 millimeters, 3 millimeters of thickness; Copper mesh (3) is measure-alike with blank sheet of paper (7), and undersized is in the cant board of organic glass support (2).

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