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Helen [10]
3 years ago
9

explain why for thousands of years people believed that stars moved across Earth's sky. Explain why we now have a different expl

anation of why stars move across the night sky. Be sure to mention reference points.
Physics
1 answer:
Anarel [89]3 years ago
6 0

Answer:

Ptolemy proposed a model, he reference system is centered on the Earth

Copernicus, proposed a deferent system,  this system is centered on the Sun, where it is at the origin of the system

Explanation:

Thousands of years ago, Ptolemy proposed a model to explain the movement of the planets and stars in the sky, in this model the reference system is centered on the Earth, so each body is orbiting in different spheres around the Earth as its center, this system had very complicated calculations and curves to be able to explain the orbits of the planets.

More recently Copernicus, proposed a deferent system, this system is centered on the Sun, where it is at the origin of the system, in this system the movement of the planets are ellipses, which is a much simpler explanation and has been widely accepted, in current systems the reference system is fixed in the bodies more massive, since this simplifies the explanation of the movements.

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Physics question help
S_A_V [24]

Answer:

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Explanation:

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8 0
2 years ago
A ray of light traveling through air strikes a piece of diamond at an angle of incidence equal to 56 degrees. Calculate the angu
Montano1993 [528]

Answer:

The angle of separation is  \Delta \theta =  0.93 ^o

Explanation:

From the question we are told that

    The angle of incidence is  \theta  _ i  = 56^o

     The refractive index of violet light  in diamond  is  n_v = 2.46

       The refractive index of red light in diamond is n_r = 2.41

      The wavelength of violet light is  \lambda _v = 400nm = 400*10^{-9}m

         The wavelength of red  light is  \lambda _r = 700nm = 700*10^{-9}m

Snell's  Law can be represented mathematically as

         \frac{sin \theta_i}{sin \theta_r} = n

Where \theta_r is the angle of refraction

=>       sin \theta_r  =   \frac{sin \theta_i}{n}

Now considering violet light

               sin \theta_r__{v}}  =   \frac{sin \theta_i}{n_v}

substituting values

                sin \theta_r__{v}}  =   \frac{sin (56)}{2.46}

                 sin \theta_r__{v}}  =  0.337

                 \theta_r__{v}}  =  sin ^{-1} (0.337)

                 \theta_r__{v}}  =  19.69^o

Now considering red light

               sin \theta_r__{R}}  =   \frac{sin \theta_i}{n_r}

substituting values

                sin \theta_r__{R}}  =   \frac{sin (56)}{2.41}

                 sin \theta_r__{R}}  =  0.344

                 \theta_r__{R}}  =  sin ^{-1} (0.344)

                 \theta_r__{R}}  = 20.12^o

The angle of separation between the red light and the violet light is mathematically evaluated as

                  \Delta \theta = \theta_r__{R}} -  \theta_r__{V}}

substituting values

                  \Delta \theta =20.12 - 19.69

                  \Delta \theta =  0.93 ^o

6 0
3 years ago
The dorsal body cavity is divided into which two cavities?
Mademuasel [1]

Answer: the dorsal cavity

Explanation:

Dorsal body cavity is the body cavity in the human body which is located posteriorly and it comprises of two type of body cavities that are cranial and the spinal. The cranial cavity is formed inside the skull and it protects the vital organ brain inside the bony protection and the spinal cavity houses the spinal cord. Thoracic cavity and pelvic cavity are the ventral cavities that means they are present in the front of the body.

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Please help I will mark brainliest!!
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Heat makes things expand, so in hot water the ballon will get bigger
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