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3 years ago

Who first used the zodiac constellations? Will Mark Brainliest!!!

1 answer:

7 0

Astronomers aren't sure who first used the zodiac constellations, but it's believed to date back to ancient Greek or Roman times.

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Can someone please help me with science.

Alina [70]

C because you need to order it from fastest to slowest and the least amount of time taken is the fastest.

8 0

3 years ago

Calculate the acceleration if you push with a 20-N horizontal force against a 2-kg block on a horizontal friction- free air tabl

Nuetrik [128]

<span>10 meters per second. The formula is F = ma, so to solve we substitute 20 for F, 2 for m and then solve for a. 20 divided by 2 - 10, therefore the acceleration is 10 meters per second.</span>

8 0

3 years ago

Light traveling from water to a gemstone strikes the surface at an angle of 80.0º and has an angle of refraction of 15.2º . (a)

7nadin3 [17]

Answer:

The the speed of light in the gemstone is $v= 0.599*10^8 m/s$

The unreasonable thing about this is that the speed of ligth in the gemstone is too low

the speed is 19% of the speed of light which is very low

One main unreasonable or inconsistent factor is that the assumption that the differnce between the angle of incidence and angle of refraction is very large

Explanation:

From the question we are told that

The angle of incidence $i = 80^o$

The angle of refraction $r = 15.2^o$

From Snell's law we have ,

$n_1 sin \theta_1 = n_2 sin \theta_2$

Where $n_1$ is the refractive index of the first medium (water) with a constant value of $n_1 = 1..333$

$n_2$ is the refractive index of the second medium (gem stone)

$\theta_1$ is the angle between the beam and perpendicular surface of the first medium

$\theta_2$ is the angle between the beam an the perpendicular surface of the second medium

Making the $n_2$ the subject of the formula

$n_2 = n_1 \frac{sin \theta_1}{sin \theta_2}$

$= (1.333)(\frac{sin (80.0)}{sin 15.2} )$

$= 5.007$

Generally refractive index of a material is mathematically represented

$n = \frac{c}{v}$

Where c is the speed light

v is the speed of light observed in a medium

Making v the subject

$v = \frac{c}{n}$

substituting value for gem stone

$v = \frac{3.0*10^8}{5.007}$

$v= 0.599*10^8 m/s$

7 0

4 years ago

A 80 kg parent and a 20 kg child meet at the center of an ice rink. They place their hands together and push. The parent pushes

Ymorist [56]

Answer:

force acting on the parent = 25 N .

Explanation:

According to third law of Newton , there is equal and opposite reaction to every action . Here force by the parent on child is action and the force by child on parent is reaction . The former is given as 25 N so force by child on parent will also be 25 N .

Answer is 25 N .

4 0

3 years ago

PHYSICAL SCIENCE : What are the advantages and disadvantages of using nuclear energy to generate electricity?

Gnesinka [82]

Nuclear energy is EXTREMELY ecofriendly, punching down any fossil fuels and even wind energy. It also is reliable, and has low emissions. However, nuclear energy is somewhat expensive and can go wrong, being dangerous to the environment and people. Along with this, uranium is finite and radioactive waste disposal is really bad.

4 0

4 years ago