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3 years ago

The redshift of a star means that _____.

Physics

2 answers:

Mamont248 [21]3 years ago

6 0

The only thing we know of that can red-shift the light of a star is motion away from us.

Gelneren [198K]3 years ago

4 0

The correct answer is D. the star is getting farther away.

When the light has red-shifted, it shows that everything is moving away from a certain point. This is known as the Doppler effect and proves the Big Bang (which would be the center point that everything is moving away from). Just as a 'for your information', blue shift is when the star is moving towards us.

Hope I helped :)

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Which formula correctly shows how to calculat the time taken, given the average velocity and the displacement

Alisiya [41]

We're so good here on Brainly, we can answer it
even WITHOUT seeing the choices.

Time = (displacement) / (magnitude of average velocity) .

8 0

3 years ago

A parallel-plate capacitor has square plates that are 7.20 cm on each side and 3.40 mm apart. The space between the plates is co

Lilit [14]

Answer:

U = 218 nJ

Explanation:

We are given;

Spacing between the plates; d = 3.4 mm = 3.4 × 10^(-3) m

Voltage across the capacitor; V = 96 V

Dimension of the square plates is 7.2cm x 7.2cm.

So, Area = 7.2 × 7.2 = 51.84 cm² = 51.84 × 10^(-4) m²

Permittivity of free space; ε_o = 8.85 × 10^(-12) C²/N.m²

From relative permeability table;

Dielectric constant of Pyrex; k1 = 5.6

Dielectric constant of polystyrene; k2 = 2.56

Now, formula for capacitance of a capacitor with Dielectric is;

C = kC_o

Where, C_o = ε_o(A/d)

Since there are 2 capacitors, d will now be d/2 = (3.4 × 10^(-3))/2 m = 1.7 × 10^(-3)

Since we have 2 capacitor, thus ;

C1 = k1*ε_o*(A/d)

C1 = (5.6 × 8.85 × 10^(-12) × (51.84 × 10^(-4))/(1.7 × 10^(-3))

C1 = 1.51 × 10^(-10) F

Similarly;

C2 = (2.56 × 8.85 × 10^(-12) × (51.84 × 10^(-4))/(1.7 × 10^(-3))

C2 = 0.691 × 10^(-10) F

For capacitors in series, formula for total capacitance(Cs) is;

1/Cs = (1/C1) + (1/C2)

Simplifying this, we have;

Cs = (C1*C2)/(C1 + C2)

Plugging in the relevant values ;

Cs = (1.51 × 10^(-10)*0.691 × 10^(-10))/((1.51 × 10^(-10)) + (0.691 × 10^(-10)))

Cs = 0.474 × 10^(-10) F

The formula for energy stored in a capacitor with 2 Dielectrics is given as;

U = ½Cs*V²

So,

U = ½ × 0.474 × 10^(-10) × 96²

U = 2.18 × 10^(-7) J = 218 × 10^(-9) = 218 nJ

8 0

3 years ago

A microwave oven operates at 2.00 ghz . what is the wavelength of the radiation produced by this appliance? express the waveleng

yan [13]

<span>Since frequency and wavelength have inverse relationship. It can be expressed by the equation: Î˝.Î» = c Where, v = frequency of the electromagnetic wave. Î» = it's wavelength c = the speed of light in a vacuum. v = 2.00 Ghz x 10^9 Hz / 1 Ghz = 2.00 x 10^9 Hz that means that in one second it covers 2.00 x 10^9 cycles. Î» = 3.10^8 m/s / 2.00 x 10^9 /s = 1.25E-10 nanometers</span>

7 0

3 years ago

15 points! Middle School Physical Science.

solniwko [45]

Answer:

1st t=d/s

2nd s=d/t

5th d=st

are all of the variations I came up with

Explanation:

the original formula for speed is s=d/t

then, I created a ratio of s/1=d/t and cross multiplied to find d=st

then, I isolated the t in one side by dividing by s on both sides.

6 0

3 years ago

Read 2 more answers

NEED HELP ASAP!! Will give Brainliest.

olga2289 [7]

a. 25 joules of work is done by the object.

Explanation:

According to the work-energy theorem, the work done ON an object is equal to the change in kinetic energy of the object, therefore:

$W=K_f -K_i= \frac{1}{2}mv^2-\frac{1}{2}mu^2$

where

$K_f = \frac{1}{2}mv^2$ is the final kinetic energy of the car, with

m = 2 kg being the mass of the car

v = 0 is the final speed of the car (brought to rest)

$K_i = \frac{1}{2}mu^2$ is the initial kinetic energy of the car, with

u = 5 m/s being the initial speed of the car

Substituting numbers, we find:

$W=\frac{1}{2}(2)(0)^2 - \frac{1}{2}(2)(5)^2=-25 J$

The negative sign means that the work done ON the car is negative: this means therefore that the work has been actually done BY the car. In fact, the car has lost its kinetic energy: this means that it has done work on the surrounding, converting its kinetic energy into other forms of energy.

Learn more about work and kinetic energy:

brainly.com/question/6763771

brainly.com/question/6443626

brainly.com/question/6536722

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5 0

3 years ago