IOAA Jr. 2022, Теория, тест с избираем отговор — Задача 3. The escape velocity
International Olympiad of Astronomy and Space Sciences for Juniors — Romania– Câmpulung Moldovenesc — October 31 - November 7 2022 — Theoretical Round — I. Multiple choice problems – 100 points · 31 октомври 2022 г.
I. Multiple choice problems – 100 points
For these problems, you have to choose only one correct answer. Please write your answer on answer-sheet. Don’t forget to write the number of the problem, i.e Grid 1. (c).
Условие
It is given: , the speed of the Earth in its circular orbit around the Sun; , the speed of a terrestrial satellite orbiting the Earth in a very low circular orbit (the first cosmic speed).
It is known that: .
The variation of the kinetic energy of the body, in relation to the Sun, is neglected during the motion of the body from the surface of the Earth to the limit of the gravitational attraction of the Earth.
The approximate minimum escape velocity of a body B, relative to the Sun, launched at a distance from the Sun equal to 1 AU, so that it leaves the Solar System forever, is:
a)
b)
c)
d) .
Отговори
- d)
Решение
Let the speed of body B at the time of its launch from Earth, in relation to the Sun, so that the body reaches the limit of the gravitational attraction of the Sun and there it is at rest in relation to the Sun. Using the details in Figure 1, in accordance with the law of conservation of mechanical energy, it follows:

representing the orbital speed of the Earth on the circular trajectory around the Sun;
representing the second cosmic speed in relation to the Sun (parabolic speed);
Conclusion: the body launched from the Earth, reaches the limit of the gravitational attraction of the Sun, in relation to the Sun, on a parabolic trajectory, with the Sun in its focus.
Оригинал в Архива: Multiple_Choice.pdf · официални решения: Grid_1.pdf · допълнителни данни: Grid_2.pdf · допълнителни данни: Grid_3.pdf · допълнителни данни: Grid_4.pdf · допълнителни данни: Grid_5.pdf · допълнителни данни: Grid_6.pdf · допълнителни данни: Grid_7.pdf · допълнителни данни: Grid_8.pdf · допълнителни данни: Grid_9.pdf · допълнителни данни: Grid_10.pdf