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worty [1.4K]
3 years ago
12

Some people wish that we lived in a recollapsing universe that would eventually stop expanding and start contracting. For this t

o be the case, which of the following would have to be true (based on current understanding)?)? (A) Dark energy is the dominant form of energy in the cosmos. (B) Dark energy does not exist and there is much more dark matter than we are aware of to date. (C) Neither dark energy nor dark matter really exist. (D) Dark energy exists but dark matter does not.
Physics
1 answer:
Monica [59]3 years ago
4 0

Answer:

(B) Dark energy does not exist and there is much more matter than current evidence suggests.

Explanation:

The repulsive force which is accelerating expansion of the universe is called as dark energy. Most of matter present in the universe is the dark matter of about eighty five percent.

So, a collapsing universe would not have the dark energy and there is more matter which is not the dark matter. This theory is rejected because expansion of the universe is observable.

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A spaceship from a friendly, extragalactic planet flies toward Earth at 0.203 0.203 times the speed of light and shines a powerf
Serjik [45]

Answer:

567.321nm

Explanation:

See attached handwritten document for more details

7 0
3 years ago
Read 2 more answers
What are 7 examples of potential energy
yaroslaw [1]

Answer:

<em>Hewo Otaku Kun Here! (UwU)</em>

Explanation:

1. A rock sitting at the edge of a cliff has potential energy. If the rock falls, the potential energy will be converted to kinetic energy.

2. Tree branches high up in a tree have potential energy because they can fall to the ground.

3. A stick of dynamite has chemical potential energy that would be released when the activation energy from the fuse comes into contact with the chemicals.

4. The food we eat has chemical potential energy because as our body digests it, it provides us with energy for basic metabolism.

5. A stretched spring in a pinball machine has elastic potential energy and can move the steel ball when released.

6. When a crane swings a wrecking ball up to a certain height, it gains more potential energy and has the ability to crash through buildings.

7. A set of double "A" batteries in a remote control car possess chemical potential energy which can supply electricity to run the car.

<em>happy to help!</em>

<em>from: Otaku Kun ^^</em>

8 0
3 years ago
3. El tambor de una lavadora que gira a 3 000 revoluciones por minuto (rpm) se acelera uniformemente hasta que alcanza las 6 000
cestrela7 [59]

Answer:

d)    α = 1693.5 rad / s² , a = 392.7 m / s² ,   a_total = α √(R² +1) ,

e)   tan θ = a / α

Explanation:

This is an exercise in linear and angular kinematics.

We initialize reduction of all the magnitudes to the SI system

   w₀ = 3000 rev / min (2π rad / 1rev) (1min / 60s) = 314.16 rad / s

   w = 6000 rev / mi = 628.32 rad / s

   θ = 12 rev = 12 rev (2π rad / 1 rev) = 75.398 rad

d) ask for centripetal, tangential and total acceleration.

Let's start by looking for centripetal acceleration, let's use the formula

          w² = w₀² + 2 α θ

          α = (w²- w₀²) / 2θ

we calculate

           α = (628.32²2 - 314.16²) / 2 75.398

           α = 1693.5 rad / s²

the quantity is linear and angular are related

         

the linear or tangential acceleration is

            a =    α  R

where R is the radius of the drum

            a = 1693.5 R

Unfortunately you do not give the radius of the drum for a complete calculation, but suppose it is a washing machine drum R = 20 cm = 0.20 m

           a = 1693.5 0.20

           a = 392.7 m / s²

the total acceleration is

           a_total = √(a² + α²)

           a_total = √ (α² R² + α²)

           a_total = α √(R² +1)

e) The centripetal acceleration is directed towards the center of the movement is radial and its magnitude is constant

Tangential acceleration is tangency to radius and its value varies proportionally radius

the total accelracicon is the result of the vector sum of the two accelerations and their directions given by trigonometry

            tan θ = a / α

the angular velocity increases linearly when with centripetal acceleration

8 0
3 years ago
A uniform solid cylinder of radius r and mass m can roll inside a hollow cylinder of radius R &gt; r without slipping. A pendulu
iogann1982 [59]

Answer: The two answers are in explanation.

Explanation: Please find the attached files for the solution

8 0
3 years ago
What is found by multiplying frequency by wavelength?
vivado [14]

That's the <em><u>speed</u></em> of the wave. 

("Velocity" is not a good way to say it, because 'velocity' always needs a direction,
and neither frequency nor wavelength tells anything about direction.)


5 0
3 years ago
Read 2 more answers
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