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3 years ago

Why were epicycles necessary in ptolemy’s model of the universe?

2 answers:

N76 [4]3 years ago

4 0

Because Mars, Jupiter, and Saturn each appear to slow down, stop, move backwards for a while, then again slow down, stop, and start moving forward again. Each plant does this at some time during each year.

If they were simply moving in circles around the Earth, they couldn't do any of this. They would need to be moving on small circles attached to the big circles. The small ones are the 'epicycles'.

Liono4ka [1.6K]3 years ago

3 0

epicycles were orbits within orbits used to explain discrepancies between expected and observed planetary movement, including the appearance of planets slowing down, speeding up, and moving backward.

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If you place a magnet under a clear dish, and sprinkle iron fillings over it, above what part of the magnet will most of the fil

xxTIMURxx [149]

round the corners of the magnet that where it is stronger

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3 years ago

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In 1610, galileo used his telescope to discover four prominent moons around jupiter. their mean orbital radii a and periods t ar

katrin2010 [14]

Time period of any moon of Jupiter is given by

$T = 2\pi \sqrt{\frac{r^3}{GM}}$

from above formula we can say that mass of Jupiter is given by

$M = \frac{4 \pi^2 r^3}{GT^2}$

now for part a)

$r = 4.22 * 10^8 m$

T = 1.77 day = 152928 seconds

now by above formula

$M = \frac{4 \pi^2 r^3}{GT^2}$

$M = \frac{4 \pi^2 (4.22 * 10^8)^3}{(6.67 * 10^{-11})(152928)^2}$

$M = 1.9* 10^{27} kg$

Part B)

$r = 6.71 * 10^8 m$

T = 3.55 day = 306720 seconds

now by above formula

$M = \frac{4 \pi^2 r^3}{GT^2}$

$M = \frac{4 \pi^2 (6.71 * 10^8)^3}{(6.67 * 10^{-11})(306720)^2}$

$M = 1.9* 10^{27} kg$

Part c)

$r = 10.7 * 10^8 m$

T = 7.16 day = 618624 seconds

now by above formula

$M = \frac{4 \pi^2 r^3}{GT^2}$

$M = \frac{4 \pi^2 (10.7 * 10^8)^3}{(6.67 * 10^{-11})(618624)^2}$

$M = 1.89* 10^{27} kg$

PART D)

$r = 18.8 * 10^8 m$

T = 16.7 day = 1442880 seconds

now by above formula

$M = \frac{4 \pi^2 r^3}{GT^2}$

$M = \frac{4 \pi^2 (18.8 * 10^8)^3}{(6.67 * 10^{-11})(1442880)^2}$

$M = 1.889* 10^{27} kg$

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3 years ago

Which wave characteristics is defined as the number of cycles of a periodic wave occurring per unit time?

Assoli18 [71]

<h3><u>Answer;</u></h3>

Frequency

<h3><u>Explanation;</u></h3>

<em><u>Waves are disturbances that travel through a material medium. There are several characteristics of waves, which includes; wavelength, frequency, period and amplitude. </u></em>
Amplitude is the maximum displacement of wave particles, or simply the height of the wave, measured in meters.
Wavelength is the distance between adjacent crests or troughs in a transverse wave or between two successive rarefaction or compressions in a longitudinal wave, measured in meters.
Period is the time it takes for one complete wave to pass a given point, measured in seconds.
<em><u>Frequency is the number of complete waves or cycles that pass a point in one second, measured is inverse seconds, or Hertz (Hz).</u></em>

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3 years ago

As the mass of an object increases, it’s inertia will

Scrat [10]

Answer:

Inertia is the property of mass that resists change. Therefore, it is safe to say that as the mass of an object increases so does its inertia.

Explanation:

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2 years ago

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A 40 kg boy is moving upwards upwards in a lift with an acceleration of 2 m /s ^2 what would be the weight felt by him if measuu

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