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  2. Kepler problem - Wikipedia

    en.wikipedia.org/wiki/Kepler_problem

    The Kepler problem and the simple harmonic oscillator problem are the two most fundamental problems in classical mechanics. They are the only two problems that have closed orbits for every possible set of initial conditions, i.e., return to their starting point with the same velocity (Bertrand's theorem). [1]: 92

  3. Cooper test - Wikipedia

    en.wikipedia.org/wiki/Cooper_test

    This is not exactly a Cooper test but a reasonable practical compromise as long as the distance is of sufficient length to put a continuous load on the cardiovascular system for 10 or more minutes. For example, the British Army uses 1.5 miles, the Australian Army uses 2.4 kilometers, the US Army uses 2 miles and the US Marine Corps 3 miles.

  4. Classical central-force problem - Wikipedia

    en.wikipedia.org/.../Classical_central-force_problem

    In classical mechanics, the central-force problem is to determine the motion of a particle in a single central potential field.A central force is a force (possibly negative) that points from the particle directly towards a fixed point in space, the center, and whose magnitude only depends on the distance of the object to the center.

  5. Hill sphere - Wikipedia

    en.wikipedia.org/wiki/Hill_sphere

    The actual Hill radius for the Earth-Moon pair is on the order of 60,000 km (i.e., extending less than one-sixth the distance of the 378,000 km between the Moon and the Earth). [ 9 ] In the Earth-Sun example, the Earth ( 5.97 × 10 24 kg ) orbits the Sun ( 1.99 × 10 30 kg ) at a distance of 149.6 million km, or one astronomical unit (AU).

  6. Space travel under constant acceleration - Wikipedia

    en.wikipedia.org/wiki/Space_travel_under...

    Force is applied by ion engines fed with material mined from the asteroid itself. In the Revelation Space series by Alastair Reynolds, interstellar commerce depends upon "lighthugger" starships which can accelerate indefinitely at 1 g, with superseded antimatter powered constant acceleration drives. The effects of relativistic travel are an ...

  7. Orders of magnitude (length) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(length)

    1.280 km – span of the Golden Gate Bridge (distance between towers) [139] 1.609 km – 1 statute mile; 1.852 km – 1 nautical mile, equal to 1 arcminute of latitude at the surface of the Earth [140] 1.991 km – span of the Akashi Kaikyō Bridge [141] 2.309 km – axial length of the Three Gorges Dam, the largest dam in the world located in ...

  8. Escape velocity - Wikipedia

    en.wikipedia.org/wiki/Escape_velocity

    Escape speed at a distance d from the center of a spherically symmetric primary body (such as a star or a planet) with mass M is given by the formula [2] [3] = = where: G is the universal gravitational constant (G ≈ 6.67 × 10 −11 m 3 ⋅kg −1 ⋅s −2 ‍ [4])

  9. Distance - Wikipedia

    en.wikipedia.org/wiki/Distance

    A metric or distance function is a function d which takes pairs of points or objects to real numbers and satisfies the following rules: The distance between an object and itself is always zero. The distance between distinct objects is always positive. Distance is symmetric: the distance from x to y is always the same as the distance from y to x.