Answer:
The Ptolemaic model of the universe <u><em>A) explained and predicted the motions of the planets with deferents and epicycles.</em></u>
Explanation:
Ptolemy of Alexandria built an explanation of the observed movements of the planets that remained in force for thirteen centuries. Ptolemy proposed a model of the Universe with the Earth in the center. In the model, the Earth remains stationary while the planets, the Moon and the Sun describe complicated orbits around it. In other words, Ptolemy devised a system in which he used epicycles, deferential and eccentric, and it was necessary to introduce an equating point to reproduce planetary movements. He proposed that:
a) Each planet revolves with constant velocity around a circle called an epicycle.
b) The center of the epicycle is located and moves with constant velocity around another circle called deferential.
c) The center of the deferent is located at a moving point, which travels with constant speed describing another circumference called eccentric.
d) The center of the eccentric coincides with the center of the Universe.
e) Since the Earth is not located in the center of the Universe, but very close to it, it was necessary to introduce an equating point, which is not on Earth, and from which you can see the planet move with constant speed.
However, Ptolemy put forward this geometric theory to explain mathematically the movements and failed to adjust any system of cycles, epicycles and eccentrics that accurately represented the observed movements of the planets.
Finally, <u><em>The Ptolemaic model of the universe A) explained and predicted the motions of the planets with deferents and epicycles.</em></u>
Answer:
E=252J
Explanation:
The total mechanical energy of an object or system is given by:
E mech=K+U
Where K is the kinetic energy of the object and U is the potential energy of the object. The carriage, sitting motionless at the top of the hill, has only potential energy in the form of gravitational potential energy.
Gravitational potential energy is given by:
Ug=mgh
Where m is the mass of the object, g is the gravitational acceleration constant, and h is the height of the object above some specific reference point, in this case the ground 21 m below.
The weight of a stationary object at the surface of the earth is equal to the force of gravity acting on the object.
W=→Fg=mg
We are given that the carriage weighs 12 N, therefore mg=12N.
Ug=12N⋅21m
⇒Ug=252Nm=252J
Hope it helped, God bless you!
Karl Schwarzschild devised the first general relativity model that would adequately describe a black hole in 1916.
What is Black Hole?
A black hole is an area of spacetime with such intense gravitational pull that nothing can escape from it, not even light or other electromagnetic waves. According to general relativity theory, a compact enough mass can bend spacetime into a black hole. The event horizon is the line beyond which there is no escape.
Black holes were once thought to be a mathematical curiosity, but theoretical research in the 1960s revealed that they were actually a general prediction of general relativity.
To know more about Black Hole refer:
brainly.com/question/7866362
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