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ddd [48]
3 years ago
12

Astronomers can now report that active star formation was going on at a time when the universe was only 20% as old as it is toda

y. When astronomers make such a statement, how can they know what was happening inside galaxies way back then?A. They look at open clusters in our galaxy and extrapolate to the past.B. They look at radio emission from quasars.C. They look at the way galaxy redshifts change with time.D. They examine the spectra of extremely high-redshift galaxies.
Physics
1 answer:
pickupchik [31]3 years ago
8 0

Answer: D.

They examine the spectra of extremely high-redshift galaxies.

Explanation:

Astronomers Measure Redshift and the most accurate way to measure redshift is by using spectroscopy. When a beam of white light strikes a triangular prism it is separated into its various components (ROYGBIV). This is known as a spectrum (plural: spectra).

With an estimated distance of about 32 billion light-years (comoving distance,) or 13.4 GLY (light-travel distance,) astronomers announced it as the mostdistant astronomical  galaxy known

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A ball is attached to a string and rotates in a circle. if it takes 1.00 s to complete one revolution, what is the angular veloc
Paha777 [63]
<span>An object roating at one revokution per second has an angular velocity of 360 degrees per second or 2pi radians per second. This is found by taking the number of revolutions over a period of time and than dividing by the chosen period of time to get the velocity. There are 360 degrees or 2pi radians in one revolution.</span>
8 0
3 years ago
Explain why asleel meedle does not csink on water​
Juli2301 [7.4K]

Answer:

upthrust

Explanation:

i think it does not sink in water because of the force pulling it upwards

5 0
3 years ago
10. Explain the principle of electric motor. Write its uses.
konstantin123 [22]

Explanation:

The principle of an electric motor is based on the current carrying conductor which produces magnetic field around it. A current carrying conductor is placed perpendicular to the magnetic field so that it experiences a force.

The largest electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors are found in industrial fans, blowers and pumps, machine tools, household appliances, power tools and disk drives.

6 0
3 years ago
Se lanza verticalmente una esfera con una rapidez de 30m/se. Determinar la rapidez de la esfera a una altura de 40m (g=10m/s2)
sergeinik [125]

v^2-{v_0}^2=2a(x-x_0)

dónde v es la velocidad de la esfera, v_0 es suya velocidad inicial, a=-g la aceleración debida a la gravedad, x la posición, y x_0 la posición inicial. Tomamos x_0=0\,\mathrm m a referirse a la posición de la esfera en el momento que la esfera fue lanzada.

Entonces

v^2-\left(30\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(-10\,\dfrac{\mathrm m}{\mathrm s^2}\right)(40\,\mathrm m)

\implies v^2=100\,\dfrac{\mathrm m^2}{\mathrm s^2}\implies v=\pm10\,\dfrac{\mathrm m}{\mathrm s}

Esto nos dice que la esfera alcanza una altura de 40 m en dos momentos - una vez hacia arriba y una vez hacia abajo. Sin embargo, independientemente del signo de la velocidad, sabemos que suya magnitud es 10 m/s, y así tenemos una rapidez de 10 m/s también en ambos momentos.

4 0
3 years ago
The universal law of gravitation states that the force of attraction between two objects depends on which quantities?
Ronch [10]

Answer:

D. the masses of the objects and the distance between them

Explanation:

Gravitation is a force, a force doesn't care about the shape or density of objects, only about their masses... and distances.

And you can get it using the following equation:

f = \frac{Gm_{1}m_{2} }{d^{2} }

Where :

G is the universal gravitational constant : G = 6.6726 x 10-11N-m2/kg2

m represent the mass of each of the two objects

d is the distance between the centers of the objects.

4 0
3 years ago
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