"Special Enhancement: Satellite Orbital Change Issues and Double Star Issues" Excellent Gravity and Space Navigation PPT Courseware

Description

"Special Enhancement: Satellite Orbital Change Issues and Double Star Issues" Excellent Gravity and Space Navigation PPT Courseware

Part One: Learning Objectives

1. Be able to analyze satellite orbit changes and know the reasons for satellite orbit changes and the changes in satellite speed before and after orbit changes.

2. Master the characteristics of binary star motion, and be able to analyze and solve the period and angular velocity of binary star motion.

Satellite orbit change problem and double star problem PPT, part 2 content: 01 Exploring key points to improve literacy

1. Orbital change problem of artificial satellites

1. Overview of orbit change issues

(1) Stable operation

(2) Orbital change operation

When the satellite changes orbit, first the linear velocity v changes, which causes the required centripetal force to change, which in turn causes the orbit radius r to change.

① When the satellite decelerates, the centripetal force F required by the satellite decreases toward = m, and the gravitational force is greater than the required centripetal force. The satellite will perform pericentric motion and change its orbit to a low orbit.

② When the satellite accelerates, the centripetal force F required by the satellite increases toward = m, and the universal gravity is not enough to provide the centripetal force required by the satellite, and the satellite will move centrifugally and change its orbit to a high orbit.

2. Example analysis

(1) Spacecraft docking problem

① When the low-orbit spacecraft is docking with the high-orbit space station, let the spacecraft accelerate reasonably, make the spacecraft perform centrifugal motion along the elliptical orbit, and catch up with the high-orbit space station to complete the docking (as shown in Figure 1A).

② If the spacecraft and the space station are on the same orbit, the spacecraft cannot catch up with the space station when accelerating, because when the spacecraft accelerates, it will perform centrifugal motion and leave the orbit. Usually, the spacecraft behind is slowed down first to lower the altitude, and then accelerated to increase the altitude. Control so that the spacecraft has exactly the same speed when it catches up with the space station, as shown in Figure B.

(2) Satellite launch and orbit change issues

Example 1 (End of 2019 Tongxu County Experimental Middle School) Figure 3 is a schematic diagram of the satellite launch process. The satellite is first launched to a low-Earth circular orbit 1, then ignited to move along an elliptical orbit 2, and finally ignited again. Send the satellite into geosynchronous circular orbit 3. Orbits 1 and 2 are tangent to point Q, and orbits 2 and 3 are tangent to point P. When the satellite is operating normally on orbits 1, 2, and 3 respectively, which of the following statements is correct? yes

A. The speed of the satellite in orbit 3 is greater than the speed in orbit 1

B. The period of the satellite in orbit 3 is greater than the period in orbit 2

C. The speed of the satellite when it passes point Q on orbit 1 is greater than the speed when it passes point Q on orbit 2

D. The acceleration of the satellite when it passes point P on orbit 2 is smaller than the acceleration when it passes point P on orbit 3.

Summary and improvement

The idea of ​​​​judging the changes in speed and acceleration when satellites change orbits

1. When judging the speed of satellites in different circular orbits, you can judge based on the rule of "the farther away, the slower".

2. When judging the speed of a satellite at different points on the same elliptical orbit, it can be judged according to Kepler's second law, that is, the farther away from the central celestial body, the smaller the speed.

3. When judging how the speed of a satellite changes when it enters an elliptical orbit from a circular orbit or enters a circular orbit from an elliptical orbit, it can be analyzed based on the conditions of centrifugal motion or pericentric motion.

For training (multiple choices) (2019 Dingyuan Yucai Experimental School Final), after completing the maintenance mission of the Hubble Space Telescope, the space shuttle entered the elliptical orbit II from the circular orbit I at point A, and B is a point on orbit II , as shown in Figure 4. Regarding the motion of the space shuttle, which of the following statements are correct?

A. The speed passing through point A on track II is less than the speed passing through point B.

B. The speed of passing A on orbit Ⅱ is less than the speed of passing A on orbit Ⅰ

C. The period of motion on orbit Ⅱ is smaller than the period of motion on orbit Ⅰ

D. The acceleration passing A on orbit II is less than the acceleration passing A on orbit I

2. Double or multiple star issues

1.Double star model

(1) As shown in Figure 5, there are two planets in the universe that are close to each other and have similar masses. They are far away from other planets, and the gravitational pull of other planets on them is negligible. In this case, they They will perform uniform circular motion with the same period around a fixed point on their connection. Usually, we call such two planets "double stars".

(2)Features

① Two stars make uniform circular motion around a certain point on the line between them. The two stars have the same operating period and angular velocity.

②The centripetal force of the two stars is equal in size and is provided by the gravitational force between them.

③The sum of the orbital radii of the two stars is equal to the distance between the two stars, that is, r1+r2=L. The orbital radius is inversely proportional to the mass of the two stars.

2.Multi-star system

There are systems similar to "double stars" in the universe, such as "three-star", "four-star" and other multi-star systems. In a multi-star system:

(1) The period and angular speed of circular motion of each star are the same.

(2) The centripetal force for a certain star's circular motion is provided by the combined gravitational force of other stars.

Example 2 Two celestial bodies that are very close to each other are very far away from other celestial bodies. They each make uniform circular motions with a certain point O as the center of the line. The distance between the two remains unchanged. Scientists call such two celestial bodies is a "double star", as shown in Figure 6. It is known that the masses of the binary stars are m1 and m2 respectively, the distance between them is L, and the gravitational constant is G. Find the orbital radii r1 and r2 and the operating period T of the binary stars.

Example 3: There are some three-star systems in the universe that are far away from other stars. One of the three-star systems is shown in Figure 7. Three stars with a mass of m are located at the three vertices of an equilateral triangle. The side length of the triangle is L. Neglect The gravitational effect of other stars on them. The three stars move in a uniform circular motion around the center O of the triangle in the same plane. The gravitational constant is G. Which of the following statements is correct?

A. The angular velocity of each star in circular motion is

B. The acceleration of each star's circular motion has nothing to do with the mass of the three stars.

C. If the distance L and the mass m of each star become twice the original, then the period becomes twice the original

D. If the distance L and the mass m of each star are doubled, the linear velocity becomes four times the original

Satellite orbit change problem and double satellite problem PPT, the third part content: 02 in-class drill, implementation point by point

1. (Satellite orbit change problem) (2019·Midterm of the first semester of Qidong Middle School) During the Spring Festival of 2019, the landmark Chinese science fiction film "The Wandering Earth" was popular. In the film, in order to allow the earth to escape from the solar system, people built a giant satellite on the earth. The power engine enables the earth to complete a series of orbit changing operations. The escape process is shown in Figure 8. The earth moves on the elliptical orbit I to aphelion point B, changes orbit, and enters the circular orbit II. It runs on the circular orbit II to At point B, the orbit changes again, thus finally breaking free from the constraints of the sun. Regarding this process, which of the following statements is correct?

A. When moving along track I to point B, you need to jet forward to slow down before entering track II.

B. The period along orbit Ⅰ is smaller than the period along orbit Ⅱ

C. When running along track I, the acceleration at point A is less than the acceleration at point B.

D. During the process of running from point A to point B on track I, the speed gradually increases

2. (Satellite and spacecraft docking issues) As shown in Figure 9, the "Shenzhou 11" spacecraft and the "Tiangong 2" space laboratory launched by our country successfully rendezvous and docked automatically on October 19, 2016. Assume that before docking "Tiangong-2" and "Shenzhou-11" both make uniform circular motion around the earth. In order to achieve the docking of the spacecraft and the space laboratory, the following measures are feasible:

A. Let the spacecraft and the space laboratory run on the same orbit, and then the spacecraft accelerates to catch up with the space laboratory to achieve docking

B. Let the spacecraft and the space laboratory run on the same orbit, and then the space laboratory slows down and waits for the spacecraft to dock.

C. The spacecraft first accelerates on an orbit smaller than the orbit radius of the space laboratory. After acceleration, the spacecraft gradually approaches the space laboratory. The docking is achieved when the two speeds are close.

D. The spacecraft first decelerates on an orbit with a smaller radius than the space laboratory's orbit. After deceleration, the spacecraft gradually approaches the space laboratory, and docking is achieved when the two speeds are close.

3. (Binary star problem) Pluto and Charon, another nearby star, can be regarded as a binary star system. The mass ratio of Pluto and Charon is about 7:1, and they are moving in a uniform circular motion around a certain point O on the line connecting them. From this we can see that Pluto moves around point O

A. The orbital radius is approximately Charon's B. The angular velocity is approximately Charon's

C. The linear velocity is about 7 times that of Charon D. The centripetal force is about 7 times that of Charon

Keywords: PPT courseware for high school physics compulsory course 2 from the People's Education Press is free to download, satellite orbit change problem and double star problem PPT download, gravitation and space navigation PPT download, .PPT format;

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Update Time: 2024-10-14

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