Question

The three laws of planetary motion are given by:
A.Einstein
B.Kepler
C.Copernicus
D.Tycho Brahe

Answer 1

Hint:He was an astronomer, mathematician, and astrologer from Germany. He is a central figure in the mathematical movement of the 17th century and has Astronomia nova, Harmonices Mundi, and Epitome Astronomiae Copernicanae in his works.

Complete answer:
In astronomy and classical physics, the laws of planetary motion are laws that explain the movements of the planets in the solar system. They were derived from the German astronomer Johannes Kepler, whose study of Danish astronomer Tycho Brahe's 16th-century observations allowed him to announce his first two laws in 1609 and a third law almost a decade later, in 1618. Kepler himself never counted or clearly separated these laws from his other observations.
It is possible to state Kepler's three laws of planetary motion as follows:
1.All planets travel in elliptical orbits around the Earth, with the Sun as one of its focal points.
2. In equal periods of time, a radius vector connecting any earth to the Sun sweeps out equal regions.
3.The squares of the planets' sidereal (revolutionary) intervals are directly proportional to the cubes of their mean Sun distance.

In 1684-85, when he formulated his famous law of gravitation between the Earth and the Moon and between the Sun and the planets, postulated by him to have truth for all objects everywhere in the universe, understanding of these laws, especially the second (the law of areas), proved crucial to Sir Isaac Newton.

Newton proved that the motion of bodies subject to central gravitational force need not always obey the elliptical orbits described by Kepler's first theorem, but can take paths identified by other open conical curves; depending on the total energy of the body, the motion can be in parabolic or hyperbolic orbits.

Hence, the correct answer is option (B).

Note:The utility of the laws of Kepler applies to the orbits of satellites, both normal and artificial, as well as planetary structures and extrasolar planets. The rules do not, of course, take into account, as formulated by Kepler, the gravitational interactions (as alarming effects) of the different planets on each other. The general problem of correctly estimating the movements of more than two bodies under their reciprocal attractions is very complex; with the exception of certain special cases, analytical solutions to the three-body problem are unobtainable. It must be remembered that the laws of Kepler refer not only to gravitational forces, but also to all other inverse-square-law forces, and to the electromagnetic forces inside the atom, if due allowance is made for relativistic and quantum effects.