According to Ptolemy's model, he, too, believed in a geocentric Universe and that the planets and stars were perfect spheres, though Earth itself was not.
He further thought that the movements of the planets and stars must be circular since they were perfect and, if the motions were circular, then they could go on forever.
<h3>What is comets and shooting stars?</h3>
Shooting stars are very different from comets, although the two can be related. A Comet is a ball of ice and dirt, orbiting the Sun (usually millions of miles from Earth). ... A shooting star on the other hand, is a grain of dust or rock (see where this is going) that burns up as it enters the Earth's atmosphere.
Learn more about ptolemy's model:
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1 liter = 1000 cm^3
20cm * 20cm * 20cm = 8000 cm^3
8000/1000 = 8 liters
Since 1ml of water = 1 cm^3 = 1 grams
8 liters = 8000 grams = 8 kilograms
They both are waves but one goes faster then the other.
It should be 12 N. the force of the book on the table should be the same as the force of the table on the book.
Force = mass * acceleration
F = 15 *8 = 120 Newton
