CN204348183U - Rigid Body Collision experiment instrument - Google Patents

Abstract

The utility model discloses a rigid body collision tester, which comprises a base, a vertical plate, a rotating shaft, a straight rod, and a pendulum ball; the vertical plate is rectangular, and the vertical plate is vertically fixed on the base; It is a thin rod with uniform cross-section, one end of the straight rod is fixed on the rotating shaft and can rotate freely around the rotating shaft in the vertical plane; the pendulum ball is connected with the rotating shaft through a cycloid, and the length of the cycloid is adjustable; The height markings at the height position before and after the collision with the straight bar. The utility model can cooperate with the teaching of rigid body mechanics to visually and conveniently verify the law of conservation of angular momentum, and is beneficial to deepen students' understanding of the process and law of rigid body collisions.

Description

Rigid body collision tester

technical field

The utility model belongs to the field of physical experiment instruments, and relates to a mechanical experiment device, in particular to a rigid body collision experiment instrument.

Background technique

The collision of rigid bodies is a common problem in rigid body mechanics, for example, the collision between a stick and a ball. During the collision process, the rigid body follows the law of conservation of angular momentum, and if it is an elastic collision, it also follows the law of conservation of mechanical energy. At present, there is a lack of an experimental device to realize rigid body collision and verify the rules of rigid body collision.

Contents of the invention

The purpose of this utility model is to design a kind of rigid body collision tester that can realize rigid body collision and verify the law of conservation of angular momentum.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical solutions: including a base, a vertical plate, a rotating shaft, a straight rod, and a swing ball; the vertical plate is rectangular, and the vertical plate is vertically fixed on the base; the rotating shaft is vertically fixed in the vertical plate The upper part; the straight rod is a thin rod with uniform cross-section, one end of the straight rod is fixed on the rotating shaft and can rotate freely around the rotating shaft in the vertical plane; the pendulum ball is connected with the rotating shaft through a cycloid, and the length of the cycloid is adjustable; The equally spaced height markings are used to determine the height positions before and after the collision between the pendulum ball and the straight rod.

The utility model also includes a swing control unit for swinging the ball. The swing control unit includes a guide rail, a telescopic rod, an electromagnet, and an electromagnet controller. Moving back and forth, the other end of the telescopic rod is connected with an electromagnet for absorbing the pendulum ball, and the electromagnet controller is electrically connected with the electromagnet for controlling the adsorption and release of the pendulum ball.

Preferably, the length of the cycloid is equal to the length of the straight rod, and the mass of the straight rod is 2.45 times the mass of the pendulum ball.

Due to the adoption of the above design, the utility model can produce the following beneficial effects: adjusting the length of the cycloid can control the collision point between the pendulum ball and the straight rod; The rise height of the bar. The utility model uses intuitive and readable physical quantities to indirectly measure the size of the angular momentum, thereby verifying the law of conservation of angular momentum, which greatly simplifies the difficulty of verification. The utility model can cooperate with the teaching of rigid body mechanics, and through the collision of the rigid body, the law of conservation of angular momentum can be verified intuitively and conveniently, which is beneficial to deepening students' understanding of the process and law of the collision of the rigid body.

Description of drawings

Below in conjunction with accompanying drawing, the utility model is further described.

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a schematic diagram of measurement and verification of the utility model.

In the figure: 1. Base, 2. Vertical plate, 3. Rotating shaft, 4. Straight rod, 5. Swing ball, 6. Swing control unit, 11. Leveling screw, 21. Height marking line, 51. Cycloid, 61 . guide rail, 62. telescopic rod, 63. electromagnet, 64. electromagnet controller.

Detailed ways

As shown in Figure 1, the utility model comprises a base 1, a vertical plate 2, a rotating shaft 3, a straight rod 4, and a swing ball 5. The vertical board 2 is rectangular, and the vertical board 2 is vertically fixed on the base 1 . The rotating shaft 3 is vertically fixed on the middle and upper part of the vertical plate 2. The straight rod 4 is a homogeneous and equal-section thin rod, and one end of the straight rod 4 is fixed on the rotating shaft 3 and can freely rotate around the rotating shaft 3 in a vertical plane. The pendulum ball 5 is connected with the rotating shaft 3 by a cycloid 51, and the length of the cycloid 51 is adjustable. The vertical plate 2 is provided with equally spaced height marking lines 21 for determining the height positions before and after the collision between the pendulum ball 5 and the straight rod 4 . A leveling screw 11 for adjusting the level of the base is provided below the base 1 .

The utility model also includes the swing control unit 6 of the swing ball 5, the swing control unit 6 includes a guide rail 61, a telescopic rod 62, an electromagnet 63, an electromagnet controller 64, the guide rail 61 is fixed on the upper right part of the vertical plate 2, and the telescopic rod 62 One end of the telescopic rod 62 is movably connected on the guide rail 61 and can move back and forth along the guide rail 61, and the other end of the telescopic rod 62 is connected with an electromagnet 63 for absorbing the pendulum ball 5. The electromagnet controller 64 is electrically connected with the electromagnet 63 to control the adsorption and release of the pendulum ball 5: when the power is on, the electromagnet 63 generates magnetism to attract the pendulum ball 5, when the power is off, the electromagnet 63 loses its magnetism, and the pendulum ball 5 releases downward swing. When using the swing control unit 6, the swing ball 5 is an iron ball.

Preferably, the length of the cycloid 51 is equal to the length of the straight rod 4 , and the mass of the straight rod 4 is 2.45 times the mass of the pendulum ball 5 .

Refer to Figure 2 for the principle of measurement and verification. In this embodiment, the mass of the pendulum 5 is m ₁ , the mass of the straight bar 4 is m ₂ , the lengths of the cycloid 51 and the straight bar 4 are both L, and the height of the pendulum 5 when it swings is h ₀ , the rebound height of the pendulum ball 5 after elastic collision with the straight rod 4 is h ₁ , and the rising height of the end of the straight rod 4 is h ₂ .

According to the law of conservation of angular momentum, there are:

m ₁ v ₁ L＝Jω-m ₁ v ₂ L, namely

Jω＝m ₁ L(v ₂ -v ₁ ) (1)

In the formula, v ₁ and v ₂ are respectively the velocity before and after the collision between the pendulum ball 5 and the straight rod 4 , and J is the moment of inertia of the straight rod 4 around the rotation axis 3 .

According to the law of conservation of mechanical energy, there are:

${\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; g</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Depend on $\frac{1}{2}J{\mathrm{\&omega;}}^2=\frac{1}{2}{m}_{2}g{h}_2,J=\frac{1}{3}{m}_2{L}^2$ have to:

$\mathrm{<span\; class="notranslate">\; J\&omega;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; 3</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 3</span>}\mathrm{<span\; class="notranslate">\; g</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Substituting (2), (3) and (4) into (1), we get:

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 6</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Preferably, when That is, when the quality of the straight rod 4 is 2.45 times of the quality of the swing ball 5, the (5) formula can be simplified as:

$\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span>\sqrt{{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

During the experiment, read the values of h ₀ , h ₁ , and h ₂ in Fig. 2 through the height marking line 21, and the law of conservation of angular momentum can be verified by formula (6).

When the length of the cycloid 51 is shorter than the length of the straight rod 4, corresponding theoretical conclusions can also be obtained according to the law of conservation of angular momentum, and can be verified by this instrument, so no further discussion will be made here.

Claims (3)

1. a kind of rigid body collision experiment instrument is characterized in that: comprise base (1), vertical plate (2), rotating shaft (3), straight bar (4), pendulum ball (5); Described vertical plate (2) is Rectangular, the vertical plate (2) is vertically fixed on the base (1); the rotating shaft (3) is vertically fixed on the middle and upper part of the vertical plate (2); the straight rod (4) is a thin rod with uniform cross-section, and one end of the straight rod (4) Fixed on the rotating shaft (3), it can freely rotate around the rotating shaft (3) in the vertical plane; the pendulum ball (5) is connected with the rotating shaft (3) through the cycloid (51), and the length of the cycloid (51) is adjustable; the vertical plate (2) is provided with equally spaced height marking lines (21) for determining the height positions before and after the collision between the pendulum ball (5) and the straight rod (4). 2. The rigid body impact tester according to claim 1, characterized in that: it also comprises a swing control unit (6) of a swing ball (5), and the swing control unit (6) comprises a guide rail (61), a telescopic rod (62) , electromagnet (63), electromagnet controller (64), guide rail (61) is fixed on the upper right part of vertical plate, and one end of telescopic link (62) is movably connected on guide rail (61) and can move back and forth along guide rail (61) , the other end of telescopic rod (62) connects electromagnet (63) and is used for adsorption pendulum ball (5), and electromagnet controller (64) is connected electrically with electromagnet (63) and is used for controlling the adsorption and the pendulum ball (5) freed. 3. rigid body collision tester according to claim 1, is characterized in that: the length of described cycloid (51) is equal to the length of straight rod (4), and the quality of described straight rod (4) is pendulum ball (5) ) 2.45 times the mass.