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sattari [20]
3 years ago
12

How do scientists know our universe is older than 6500 years?

Physics
1 answer:
dmitriy555 [2]3 years ago
5 0
<span>This is because astronomers have discovered that the Crab Nebula is 6500 light years from earth. This means it takes 6500 earth years for light to get from the Crab Nebula to earth. Therefore, if we are able to observe the Crab Nebula and beyond it then it means that earth has been in existence for 6500 years and over.  </span>




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What does the term equilibrium refer to
igor_vitrenko [27]
Equilibrium<span>-the condition of a system when no observable change is taken place or the kinetic energy is equal. </span>Equilibrium means<span> to stay balanced or equal.</span>
6 0
3 years ago
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A car starting from rest accelerates in a straight line at a constant rate of 5.5m/s for 6s.If the car after this acceleration s
aalyn [17]

Answer:

The time it takes to stop is 13.75 seconds

Explanation:

A body moving with constant acceleration, 'a', for a time, 't', has a final velocity, 'v', given by the following kinematic equation;

v = u + a·t

Where;

v = The final velocity of the body

a = The acceleration of the body

t = The time of acceleration (accelerating period) of the body

u = The initial velocity of the body

The given parameters for the acceleration of the car are;

The initial velocity of the car, u = 0 m/s (a car starting from rest)

The constant acceleration of the car, a =  5.5 m/s²

The acceleration duration, t = 6 s

Therefore, we have;

The final velocity of the car after the acceleration, v = 0 m/s + 5.5 m/s² × 6 s = 33 m/s

The final velocity of the car after the acceleration, v = 33 m/s

When the car slows down uniformly, and comes to a stop (final velocity, v₂ = 0 m/s), it has a constant negative acceleration, (deceleration) '-a₂'

The given parameters when the car slows down  are;

The deceleration, -a₂ = 2.4 m/s²

The final velocity, v₂ = 0 m/s

The initial velocity, u₂ = v = 33 m/s

The time it takes to stop = t₂

-a₂ = 2.4 m/s²

∴ a₂ = -2.4 m/s²

From, v = u + a·t, we have;

v₂ = v + a₂·t₂

By plugging in the values of the variables, we have;

0 m/s = 33 m/s + (-2.4 m/s²) × t₂

∴ 2.4 m/s² × t₂ = 33 m/s

t₂ = 33 m/s/(2.4 m/s²) = 13.75 s

The time it takes to stop, t₂ = 13.75 seconds

7 0
3 years ago
If you calculate the thermal power radiated by typical objects at room temperature, you will find surprisingly large values, sev
OverLord2011 [107]

Answer:

best explanation of this is sentence B

Explanation:

The radiation emission of the bodies is given by the expression

     P = σ A e T⁴

Where P is the power emitted in watts, σ is the Stefan-Boltzmann constant, A is the surface area of ​​the body, e is the emissivity for black body e = 1 and T is the absolute body temperature in degrees Kelvin.

When the values ​​are substituted the power is quite high 2.5 KW, but the medium surrounding the box also emits radiation

   T box ≈ T room

    P box ≈ P room

As the two powers are similar and the box can absorbed, since it has the ability to emit and absorb radiation, as the medium is also close of the temperature of the box, the amount emitted is very similar to that absorbed, so the net change in energy is very small.

   In the case that the box is much hotter or colder than the surrounding medium if there is a significant net transfer.

Consequently, the best explanation of this is sentence B

5 0
3 years ago
An oil film with refractive index 1.48 and thickness 290 nm is floating on water and illuminated with white light at normal inci
VikaD [51]

Answer:

572.3 nm

Explanation:

n_{oil} = refractive index of the oil film = 1.48

t_{oil} = thickness of the oil film = 290 nm

\lambda = wavelength of the dominant color

m = order

Using the equation

2 n_{oil} t_{oil} = (m + 0.5) \lambda

For m = 0

2 (1.48) (290) = (0 + 0.5) \lambda

\lambda = 1716.8 nm

For m = 1

2 (1.48) (290) = (1 + 0.5) \lambda

\lambda = 572.3 nm

For m = 2

2 (1.48) (290) = (2 + 0.5) \lambda

\lambda = 343.4 nm

Hence the dominant color wavelength is 572.3 nm

8 0
3 years ago
QUESTION 1<br> 67.2 kilometers = how many decameters
den301095 [7]

Answer: the answer should be 6,720 decameters.

6 0
3 years ago
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