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Anon25 [30]
3 years ago
14

Perhaps the greatest of the Greek astronomers, Hipparchus compiled the first catalog of stars, 49) accurately measured their pos

itions, and defined the basic system of stellar brightnesses which we now call the magnitude system. A particular star in his catalogue has an apparent magnitude of 4 and an absolute -12. Determine the distance to the star.
Physics
1 answer:
Sergio039 [100]3 years ago
7 0

Answer:

Explanation:

it would be 3 because ju divide 12 by 4

You might be interested in
An airplane accelerates from a speed of 88m/s to a speed of 132 m/s during a 15 second time interval. How far did the airplane t
Gelneren [198K]

Answer:

1650\:\mathrm{m}

Explanation:

We can use the following kinematics equations to solve this problem:

v_f=v_i+at,\\{v_f}^2={v_i}^2+2a\Delta x.

Using the first one to solve for acceleration:

132=88+a(15),\\15a=44,\\a=\frac{44}{15}=2.9\bar{3}\:\mathrm{m/s^2}.

Now we can use the second equation to solve for the distance travelled by the airplane:

132^2=88^2+2\cdot2.9\bar{3}\cdot \Delta x,\\\Delta x= \frac{9680}{2\cdot2.9\bar{3}},\\\Delta x =\fbox{$ 1650\:\mathrm{m}$}(three significant figures).

6 0
3 years ago
We can see our face clearly on mirror why cant we see our face clear on aluminium or irion plate
Simora [160]

Because specular reflection occurs with a mirror, while diffuse reflection occurs with aluminium or iron plate

Explanation:

Reflection is a phenomenon typical of waves (such as light wave), that occurs when a wave bounces off the surface of a certain material, going back into the original medium at a certain angle, without changing speed, frequency or wavelength.

The direction of the reflected ray is given by the law of reflection, which states that:

  • The incoming ray, the reflected ray and the normal to the surface all lie on the same plane
  • The angle of incidence is equal to the angle of reflection

Depending on the type of surface, two different types of reflection can occur:

  • Specular reflection: this occurs when the surface is perfectly smooth. In such a case, all the incoming rays of light hit the surface with same angle of incidence, therefore they are reflected at the same angle. This means that a perfect and clear image of the original object can be formed: this is the case of a mirror.
  • Diffuse reflection: when the surface is not smooth, the imperfections on the surface are such that the incoming rays of light hit the surface at different angles of incidence. As a result, the rays are reflected at different angles to each other, and therefore no clear image of the object is produced. This is the case of aluminium or iron plate.

Learn more about reflection and other wave phenomena:

brainly.com/question/3183125

brainly.com/question/12370040

#LearnwithBrainly

8 0
3 years ago
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is v = 1/ κμ0ε0 , where κ is the dielectri
vladimir1956 [14]

Answer:

v=2.24\times 10^{8}\ m/s

Explanation:

Given that,

The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

v=\dfrac{1}{\sqrt{k\mu_o\epsilon_o}}

Where

k is the dielectric constant of the substance.

v is the speed of light in water

c=\dfrac{1}{\sqrt{1.78\times 4\pi \times 10^{-7}\times 8.85\times 10^{-12}}}

v=2.24\times 10^{8}\ m/s

So, the speed of light in water is 2.24\times 10^{8}\ m/s

7 0
4 years ago
HELP ASAP!!! PLEASE!!!! A driver traveling on the highway at 100km/hr notices the speed limit changes to 50km/hr as a speed came
Talja [164]

Answer:

90m

Explanation:

Speed * time

100*0.9=90m

hope this helped xx

8 0
3 years ago
Mercury is commonly used in thermometer give reasons​
evablogger [386]

Answer:

hi

<h3>BECAUSE MERCURY IS USED BECAUSE IT is the only liquid available in room temperature </h3>

Explanation:

pls mark as a BRAINLIST

6 0
3 years ago
Read 2 more answers
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