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3 years ago

Hubble law how did astronomers gather the information needed to establish the law?

1 answer:

7 0

They measured the wavelength of light emitted by stars using spectrometers and found it was being redshifted.
This implied the stars were moving away aka the space between the scientists and the star was expanding

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A group of students conduct an experiment with a block of wood sliding down an incline. They find that the final energy of the b

77julia77 [94]

Answer:

1) 51 m

2) Some energy was transformed to other forms. (This question)

3) 3.24 J

4) 45 J

5) 1020 J

Explanation:

100%

8 0

3 years ago

What rock type would most likely be found in the location marked by the black rectangle in the diagram below?

pychu [463]

There is no diagram below so I can't answer the question

5 0

3 years ago

Read 2 more answers

A 525 kg satellite is in a circular orbit at an altitude of 575 km above the Earth's surface. Because of air friction, the satel

Dafna1 [17]

Answer:

$1.69\cdot 10^{10}J$

Explanation:

The total energy of the satellite when it is still in orbit is given by the formula

$E=-G\frac{mM}{2r}$

where

G is the gravitational constant

m = 525 kg is the mass of the satellite

$M=5.98\cdot 10^{24}kg$ is the Earth's mass

r is the distance of the satellite from the Earth's center, so it is the sum of the Earth's radius and the altitude of the satellite:

$r=R+h=6370 km +575 km=6945 km=6.95\cdot 10^6 m$

So the initial total energy is

$E_i=-(6.67\cdot 10^{-11})\frac{(525 kg)(5.98\cdot 10^{24} kg)}{2(6.95\cdot 10^6 m)}=-1.51\cdot 10^{10}J$

When the satellite hits the ground, it is now on Earth's surface, so

$r=R=6370 km=6.37\cdot 10^6 m$

so its gravitational potential energy is

$U = -G\frac{mM}{r}=-(6.67\cdot 10^{-11})\frac{(525 kg)(5.98\cdot 10^{24}kg)}{6.37\cdot 10^6 m}=-3.29\cdot 10^{10} J$

And since it hits the ground with speed

$v=1.90 km/s = 1900 m/s$

it also has kinetic energy:

$K=\frac{1}{2}mv^2=\frac{1}{2}(525 kg)(1900 m/s)^2=9.48\cdot 10^8 J$

So the total energy when the satellite hits the ground is

$E_f = U+K=-3.29\cdot 10^{10}J+9.48\cdot 10^8 J=-3.20\cdot 10^{10} J$

So the energy transformed into internal energy due to air friction is the difference between the total initial energy and the total final energy of the satellite:

$\Delta E=E_i-E_f=-1.51\cdot 10^{10} J-(-3.20\cdot 10^{10} J)=1.69\cdot 10^{10}J$

8 0

3 years ago

Which of the following statements is true? The square root of the molecular weight of a gas is equal to its rate of diffusion. T

forsale [732]

The diffusion coefficient of the gas is proportional to the average rate of thermal motion of the molecules.

the average velocity is inversely proportional to the square root of the molar mass

so
The gas diffusion rate is inversely proportional to the square root of its molecular weight.

8 0

3 years ago

Read 2 more answers

The rest deltoid row is a back exercise true or false

bixtya [17]

False because your deltoids are in your shoulders not your back

3 0

3 years ago