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3 years ago

5

Scientists can measure the amounts of different elements found in the universe. Which element's concentration in the universe is

evidence for the big bang theory?
A. Helium
B. Uranium
C. Calcium
D. Iron

1 answer:

fgiga [73]3 years ago

5 0

Uranium is the correct answer

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Which is an example of a wave?

Travka [436]

Answer:

The answer is A

Explanation:

Someone shouting to you from across a room

4 0

2 years ago

Read 2 more answers

Which of the following changes would cause the fusion rate in the Sun’s core to increase? Check all that apply. View Available H

fredd [130]

Answer:

1. An increase in the core temperature

2. A decrease in the core radius.

Explanation:

The sun is a Main Sequence star. A Main Sequence star is powered by fusing hydrogen into Helium within its core.

For this fusion to take place, a temperature of at least 10 million Kelvin is required, beyond this point, the fusion rate is directly related to the core temperature. If the temperature increases, the fusion rate will greatly increase.

Something similar happens if the core reduces its radius. This can happen at the end of the star's lifetime, shortly before it becomes a red giant. Once the hydrogen is depleted, the core will start to shrink because the force of gravity, and as it gets smaller, gets more compressed, and its temperature increases. The outer layers of remaining Hydrogen that were outside the core now begin to heat up, and as the core continues to shrink, the star gets hot enough to begin the fusion process again, and the fusion rate can even be higher than it was during the first phase of the star, as the star becomes a Red Giant.

7 0

3 years ago

The gravitational force of attraction be-

Sliva [168]

Answer:

2.15 m

Explanation:

Newton's Law of Universal Gravitation:

$\displaystyle F_g = G \frac{m_1 m_2}{r^2}$

$\displaystyle F_g$ is the gravitational force of attraction

$\displaystyle G$ is the universal gravitational constant

$m_1$ and $m_2$ are the two masses of the two objects

$\displaystyle r$ is the distance between the centers of the two objects.

List the known values:

$\displaystyle F_g = 3.47 \cdot 10^-^8 \ \text{N}$
$\displaystyle G = 6.673 \cdot 10^-^1^1 \ \frac{Nm^2}{kg^2}$
$\displaystyle m_1 = 44.8 \ \text{kg} \\ m_2 = 53.9 \ \text{kg}$
$\displaystyle r =\ ?$

Plug these values into the equation:

$\displaystyle 3.47 \cdot 10^-^8 \ \text{N} = 6.673 \cdot 10^-^1^1 \ \frac{Nm^2}{kg^2} \frac{(44.8 \ \text{kg})(53.9 \ \text{kg})}{r^2}$

Notice that the units $\displaystyle \text{N}$ , $\displaystyle \text{kg}^2$ , and $\displaystyle \text{m}$ cancel out. We are left with the unit $\displaystyle \text{m}$ for radius r.

Get rid of the units to make the problem easier to read.

$\displaystyle 3.47 \cdot 10^-^8= 6.673 \cdot 10^-^1^1 \ \frac{(44.8)(53.9) \ }{r^2}$

Multiply the masses together.

$\displaystyle 3.47 \cdot 10^-^8= 6.673 \cdot 10^-^1^1 \ \frac{(2414.72)}{r^2}$

Multiply the gravitational constant and the masses together.

$\displaystyle 3.47 \cdot 10^-^8= \frac{1.61134265\cdot 10^-^7}{r^2}$

Solve for $r^2$ by dividing both sides by 3.47 * 10^(-8) and moving $r^2$ to the left.

$\displaystyle r^2 = \frac{1.61134265\cdot 10^-^7}{3.47\cdot 10^-^8}$
$r^2 = 4.64363876$

Take the square root of both sides.

$r=2.154910383$

The students are sitting about 2.15 m apart from each other.

4 0

3 years ago

Suppose you have an unknown clear substance immersed in water, and you wish to identify it by finding its index of refraction. Y

s344n2d4d5 [400]

Answer: 1.65

Explanation: Snell's law says that index of refraction of the first material times sine theta one equals index of refraction of the second material, which we don't know, multiplied by sine theta two, . So, we'll solve this for N two by dividing both sides by sine theta two. So, N two is N one sine theta one over sine theta two . So, that's 1.33 index of refraction of water times sine of 45.7degrees incidence angle divided by sine of 30.5 degrees angle of refraction, giving us 1.65.

The formula for snell's law is N1*sintheta1=N2*sinetheta2

3 0

3 years ago

which of the following does not represent a significant negative environmental impact of using nuclear fuel

Brrunno [24]

Nuclear energy has practically no harmful emission (unless you consider water vapour to be bad).

3 0

3 years ago