Which of the following statements are true? (mark all that apply)
A) Adaptive optics corrects for atmospheric distortion by following the distortion of a bright star, possibly an artificial star created by a laser, and rapidly changing the shape of a mirror using computer-controlled actuators to compensate for the distortion.
B) Improvements in technology will eventually allow the entire electromagnetic spectrum to be observed from high mountaintop observatories.
C) X rays from astronomical objects can only be detected from telescopes in space or in high altitude rockets.
D) The best observing sites for optical telescopes are atop remote mountains.
E) Radio telescopes must be carried to high altitudes by balloons in order to detect this type of radiation.

Answer:

[tex]\boxed{V_{i} = 5\ m/s}[/tex]

Explanation:

Given:

Acceleration = a = 0.75 m/s²

Time = t = ?

Final Velocity = [tex]V_{f}[/tex] = 72 km/hr = 20 m/s

Required:

Initial Velocity = [tex]V_{i}[/tex] = ?

Formula:

a = [tex]\frac{V_{f}-V_{i}}{t}[/tex]

Solution:

For  [tex]V_{i}[/tex]  the formula becomes:

[tex]V_{i} = V_{f}-at[/tex]

[tex]V_{i}[/tex]  = 20 - (0.75)(20)

[tex]V_{i}[/tex]  = 20 - 15

[tex]V_{i}[/tex]  = 5 m/s

In Case: If you want it in km/hr:

[tex]V_{i}[/tex]  = 5 * 3.6

[tex]V_{i}[/tex]  = 18 km/hr

Answer:

5 m/s

Explanation:

acceleration = 0.75 m/s²

time = 20 s

final velocity = 72 km/h = 20 m/s

initial velocity = ?

Apply formula for initial velocity.

[tex]u=-at+v[/tex]

[tex]\sf a=acceleration\\t=time\\v=final \: velocity\\u=initial \: velocity[/tex]

Solve for u.

[tex]u=-(0.75)(20)+ 20[/tex]

[tex]u=-15+20[/tex]

[tex]u= 5[/tex]

Answer:

Option B. 10 V.

Explanation:

The following data were obtained from the question:

Resistor 1 (R₁) = 20 Ω

Resistor 2 (R₂) = 40 Ω

Resistor 3 (R₃) = 60 Ω

Potential difference (V) = 60 V

Next, we shall determine the total resistance of the circuit.

The circuit is in series connection. Therefore the total resistance (R) can be obtained by adding up R₁, R₂ and R₃ together as shown below:

R = R₁ + R₂ + R₃

R = 20 + 40 + 60

R = 120 Ω

Therefore, the total resistance in the circuit is 120 Ω

Next, we shall determine the current flowing in the circuit.

Note: The same current will flow through each resistor since they are in series connection.

The current flowing in the circuit can be obtained as follow:

Potential difference (V) = 60 V

Total resistance (R) = 120 Ω

Current (I) =..?

V = IR

60 = I x 120

Divide both side by 120

I = 60/120

I = 0.5 A

Therefore, the current flowing in the circuit is 0.5 A

Now, we can calculate the potential drop across R₁ as follow:

Resistor 1 (R₁) = 20 Ω

Current (I) = 0.5 A

Potential difference cross R₁ (V₁) =.?

V₁ = IR₁

V₁ = 0.5 x 20

V₁ = 10 V

Therefore, the potential difference across R₁ is 10 V.

Answer:

It would not be safe to walk out to where waves are breaking due to the effect of rip currents

Explanation:

The water depth in the surf zone is between 5 to 10 meters deep and with a wavelength of 30 meters, the speed of the wave is considerably fast such that control for safety may be difficult

Also the speed of the wave is directly related to the depth of the water which means that where the wave described above is fast as well as the rip current, also the water depth is expected to be considerable for a non swimmer

It is best to seek for sign post regarding safe areas and do not go into the water where there are no lifeguards or marked safe zones.

It won't be safe to walk out to where the waves are breaking.

This is because the wavelength is 30 meters which is a characteristic of

areas with significant water depth in the range of 5-11 meters.Under these

conditions the waves are usually very fast and may get swept with the

current from the water waves when trying to run from it.

It is recommended that we stay in areas where the depth is noted as not

being much and should always seek help and clarity from the life guards so

as to prevent drowning and death.

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Answer:

8996kg*m/s/s

Explanation:

Given:

a=26m/s/s

m=346kg

Required:

f=?

Formula:

f=m*a

Solution:

f=346kg*26m/s/s

f=8996kg*m/s/s

Hope this helps ;) ❤❤❤

Answer:

[tex]\boxed{F = 8996 \ Newton}[/tex]

Explanation:

Given:

Mass = m = 346 kg

Acceleration = a = 26 m/s²

Required:

Force = F = ?

Formula:

F = ma

Solution:

F = 346 * 26

F = 8996 Newton

Answer:

λ = 1.8 x 10⁻⁷ m = 180 nm

Explanation:

First we find the work function of tungsten by using the following formula:

∅ = hc/λmax

where,

∅ = work function = ?

h = Plank's Constant = 6.626 x 10⁻³⁴ J.s

c = speed of light = 3 x 10⁸ m/s

λmax = maximum wavelength for photoelectric emission = 230 nm

λmax = 2.3 x 10⁻⁷ m

Therefore,

∅ = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(2.3 x 10⁻⁷ m)

∅ = 8.64 x 10⁻¹⁹ J

Now we convert Kinetic Energy of electron into Joules:

K.E = (1.5 eV)(1.6 x 10⁻¹⁹ J/1 eV)

K.E = 2.4 x 10⁻¹⁹ J

Now, we use Einstein's Photoelectric Equation:

Energy of Photon = ∅ + K.E

Therefore,

Energy of Photon = 8.64 x 10⁻¹⁹ J + 2.4 x 10⁻¹⁹ J

Energy of Photon = 11.04 x 10⁻¹⁹ J

but,

Energy of Photon = hc/λ

where,

λ = wavelength of light = ?

Therefore,

11.04 x 10⁻¹⁹ J = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/λ

λ = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(11.04 x 10⁻¹⁹ J)

λ = 1.8 x 10⁻⁷ m = 180 nm

Answer:

u=36.8m/s

Explanation:

because of the acceleration is a constant acceleration we can use one of the "SUVAT" equations

u^2=v^2-2ā*s. where:

u^2 stands for intial velocity

v^2 stands for final velocity

since the cougar skidded to a complete stop the final velocity is zero.

u^2=v^2-2ā*s

u^2=(0)^2 -2(-2.87 m/s^2)*236 m

u^2=0+5.74m/s^2* 236m

u^2=1354.64m^2/s^2

u=√1354.64m^2/s^2

u=36.8m/s (approximate value)

when ever the acceleration is constant you can use one of the following equation to find the required value.

1. v = u + at. (no s)

2. s= 1/2(u+v)t. (no ā)

3. s=ut + 1/2at^2. ( no v)

4. v^2=u^2 + 2āS. (no t). 5. s= vt - 1/2at^2. (no u)

Answer:

5.23 C

Explanation:

The current in the wire is given by I = ε/R where ε = induced emf in the wire and R = resistance of wire.

Now, ε = -ΔΦ/Δt where ΔΦ = change in magnetic flux = AΔB and A = area of loop and ΔB = change in magnetic field intensity = B₂ - B₁

B₁ = 0.670 T and B₂ = 0 T

ΔB = B₂ - B₁ = 0 - 0.670 T = - 0.670 T

A = πD²/4 where D = diameter of circular loop = 13.2 cm = 0.132 m

A = π(0.132 m)²/4 = 0.01368 m² = `1.368 × 10⁻² m²

ε = -ΔΦ/Δt = -AΔB/Δt = -1.368 × 10⁻² m² × (-0.670 T)/Δt= 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire R = ρl/A' where ρ = resistivity of copper wire =  1.68 x 10⁻⁸ Ω.m, l = length of wire = πD and A' = cross-sectional area of wire = πd²/4 where d = diameter of wire = 2.25 mm = 2.25 × 10⁻³ m

R = ρl/A' = 1.68 x 10⁻⁸ Ω.m × π × 0.132 m÷π(2.25 × 10⁻³ m)²/4 = 0.88704/5.0625 = 0.1752 × 10⁻² Ω = 1.752 × 10⁻³ Ω

So, I = ε/R = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

IΔt = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω = 0.5232 × 10 C

Since ΔQ = It = 5.232 C ≅ 5.23 C

So the charge is 5.23 C

The induced emf through wire depends on the current flow (indirectly with charge flow as well).

The value of charge moving past a point in the coil during its operations is 5.23 C.

The region in a space where a particle experiences some magnetic force, is known as the magnetic field.

Given data -

The diameter of the circular loop is, d = 13.2 cm = 0.132 m.

The change in magnetic field strength is, ΔB = 0.670 T.

The new diameter of the wire is, d' = 2.25 mm = 2.25 × 10³ m.

The resistivity of the wire is, [tex]\rho = 1.68 \times 10^{-8} \;\rm \Omega.m[/tex].

The current in the wire is given by the following expression,

I = ε/R

Here,

ε is the induced emf in the wire.

R is the resistance of the wire.

And the expression for the induced emf of the wire is given as,

ε = -ΔΦ/Δt

Here,

ΔΦ is the change in magnetic flux. And its expression is,

ε = A × ΔB

Here,

A is the area of the loop. And its value is, A = πd²/4.

Solving as,

A = π(0.132 m)²/4

A = 0.01368 m²
A = `1.368 × 10⁻² m²

Now, calculating the induced emf as,

ε = ΔΦ/Δt

ε = A × ΔB/Δt

ε = 1.368 × 10⁻² m² × (0.670 T)/Δt

ε = 0.9166 × 10⁻² Tm²/Δt

Now, the resistance R of the circular wire is,

R = ρ × L/A'

Here,

L is the length of the wire and its value is. L = πd .

And A' is the new cross-sectional area of wire,

A' = πd'²/4

So, the resistance is,

R = ρ × L/A'

R = 1.68 x 10⁻⁸  ×( π × 0.132 m) ÷ π(2.25 × 10⁻³ m)²/4 =

R = 0.88704/5.0625

R = 0.1752 × 10⁻² Ω

R = 1.752 × 10⁻³ Ω

Now, the current flow (I) in the wire is given as,

I = ε/R

I = 0.9166 × 10⁻² Tm²/Δt1.752 × 10⁻³ Ω  

And obtaining the value of charge from the expression of current as,

Q = IΔt
Q = 0.9166 × 10⁻² Tm²/1.752 × 10⁻³ Ω

Q = 0.5232 × 10 C

Q = 5.23 C

Thus, we can conclude that the value of charge moving past a point in the coil during its operations is 5.23 C.

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Answer:

The magnetic field remains the same.

Explanation:

If a solenoid has length L, N windings, and radius b, then the magnetic field inside the solenoid is given by :

[tex]B=\mu_o NI[/tex]

[tex]\mu_o[/tex] is magnetic permeability

If the radius of the solenoid were doubled and all other quantities remained the same, the magnetic field inside the solenoid would remains the same as it is independent of the radius of the solenoid.

Answer:

[tex] 2.18\times 10^{-30} \:J[/tex]

Explanation:

[tex] K.E._{Electron}= \frac{1}{2} mv^2 \\\\

= \frac{1}{2} \times 9.11\times 10^{-31}\times (2.19\times 10)^2 \\\\

=4.555\times 10^{-31}\times 4.7961\times 10^2 \\\\

=4.555\times 10^{-31+2}\times 4.7961 \\\\

=21.8462355\times 10^{-29}\\

=2.18462355\times 10^{-30}\\

=2.18\times 10^{-30} \:J\\[/tex]

Answer:

personally I'd say C by do not know if that is the exact answer

Answer:

Friction force always acts tangent to the surface at points of contact. Friction force acts opposite to the direction of motion.

Explanation:

Answer:

[tex]E=6.01\times 10^{-3}\ J[/tex]

Explanation:

It is given that,

Side of a square loop, l = 24 cm = 0.24 m

Resistance of loop, R = 6.1 ohms

Initial magnetic field is 0.665 T and final magnetic field is 0 as the field is removed in 40 ms

We need to find the electrical energy dissipated in this process.

Due to change in magnetic field, the loop will induce a voltage. The induced voltage is given by :

[tex]V=-\dfrac{dB}{dt}\\\\V=\dfrac{BA}{t}[/tex]

If I is induced current then,

[tex]V=IR[/tex]

[tex]I=\dfrac{V}{R}\\\\I=\dfrac{BA}{tR}[/tex]

Power is given by voltage times current. So,

[tex]P=\dfrac{(BA)^2}{(t^2R)}[/tex]

Now, energy is given by the product of power and time. So,

[tex]E=\dfrac{(BA)^2}{(t^2R)}\times t\\\\E=\dfrac{(BA)^2}{(tR)}[/tex]

Now putting all the values in above formula. So,

[tex]E=\dfrac{(0.665\times (0.24)^2)^2}{(40\times 10^{-3}\times 6.1)}\\\\E=6.01\times 10^{-3}\ J[/tex]

So, the electrical energy of [tex]6.01\times 10^{-3}\ J[/tex] is dissipated in this process.

The electrical energy dissipated throughout this process will be "6.01 × 10⁻³ J".

According to the question,

Square loop's side, l = 24 cm or,

                                  = 0.24 m

Loop's resistance, R = 6.1 ohms

Initial magnetic field = 0.665 T

Final magnetic field = 0

We know the relation,

→ V = - [tex]\frac{dB}{dt}[/tex]

      = [tex]\frac{BA}{t}[/tex]

Also we know,

Current, V = IR

               I = [tex]\frac{V}{R}[/tex]

                 = [tex]\frac{BA}{tR}[/tex]

Now, Energy, E = [tex]\frac{(BA)^2}{t^2R}[/tex] × t or,

                          = [tex]\frac{(BA)^2}{tR}[/tex]

By substituting the values,

                          = [tex]\frac{(0.665\times (0.24)^2)^2}{40\times 10^{-3}\times 6.1}[/tex]

                          = 6.01 × 10⁻³ J

Thus the response above is correct.                                  

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Answer:

B. they have less mass than their reactants

Explanation:

In both nuclear fission and nuclear fusion, the products have less mass than their reactants. So, option B is correct.

Nuclear reaction is defined as the reaction that involves the collision between one or more atomic nuclei and a highly energetic subatomic particle to produce one or more nuclei along with the emission of a large amount of energy.

Here,

Nuclear fission and fusion are two types of nuclear reactions that involves the production of large amount of energy from atomic nuclei.

Nuclear fission is the nuclear reaction in which a heavier nucleus is split into two or more lighter nuclei, under radioactive condition, with the release of a massive amount of energy.

Nuclear fusion is the nuclear reaction in which two or more lighter nuclei nuclei fuse together under radioactive condition and forms a heavier nuclei and by releasing a large amount of energy.

In both nuclear fission and nuclear fusion, there occurs a release of large amount of energy. This is because most of the mass of the reactants is converted into energy which is known as the mass-energy. So the products of these nuclear reactions will have lesser mass than their reactants.

Hence,

In both nuclear fission and nuclear fusion, the products have less mass than their reactants.

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Explanation:

let us use the explanation below to get the intuition so desired;

According to Faraday's law of electro magnetic induction, when ever a coil/conductor is made to rotate in a magnetic field, voltage or emf is created and current is produced, in the long run energy has be produced or converted.

The conversion of this energy is made possible by the motion of the coil/conductor is the magnetic field, just by the  motion of the conductor cutting through the magnetic field, thus creating electro motive force(E.M.F) hence producing current, and ultimately energy is created

Answer:

It is a finite resource.

Explanation:

A nonrenewable resource is a natural substance that is not replenished with the speed at which it is consumed. Fossil fuels such as oil, natural gas, and coal are examples of nonrenewable resources.

Answer:

Coal, oil, natural gas.

Explanation:

Non renewable resource -A non-renewable resource (also called a finite resource) is a natural resource that cannot be readily replaced by natural means at a quick enough pace to keep up with consumption.

Coal, oil, and natural gas are all examples of non-renewable resources and cannot be readily replaced to keep up with consumption.

Answer:

3.94

Explanation:

divide total mass by the number of blocks since they are identical

Answer:

3.94

Explanation:

You want to find the mass of one block. Since we know there is 8 blocks with the same mass, you can divide the total mass by 8 since the mass is equally distributed within the 8 blocks

Answer:

a) Volt

Explanation:

The standard metric unit on electric potential difference is the volt.

answer

all of the above

explanation

as we know that the si unit of potential difference is volt

which is equal to j/c and j/c is equal to j/a.s so the correct answer is all of the above

Answer:

theory

Explanation:

A scientist can contribute to the formation of a theory in a particular subject by conducting research along the line of that subject.

Conducting research requires the formation of a hypothesis and testing the hypothesis by conducting a relevant experiment during which data are gathered, analyzed, and interpreted in order to falsify or accept the hypothesis.

A good experiment must be replicate-able. When the same experiment is repeated by different independent researchers and the same conclusion is arrived at, this could potentially lead to the formation of a theory.

Hence, a scientist can contribute to the formation of a theory by conducting an experiment with replicability in order to test a hypothesis.

Answer:

Mid ocean ridges are evidence of sea floor spreading as tectonic movement opens a gash or "fault" in the ocean floor.

Answer:

Eruptions of molten material, magnetic stripes in the rock of the ocean floor, and the ages of the rocks themselves; this evidence led scientists to look again at Wegener's hypothesis of continental drift.

The current does not change.

All three resistors are connected directly to the power source, and are unaware of each other.

Answer:

It emits alpha and beta particles.

Explanation:

EDG 20

Answer:

the answer is b, calcium-45

Explanation:

Answer:

Net force = 0

Explanation:

Short answer: if the middle book is not acceleration in any direction, the net force is zero.

Long answer: refer to the attached free-body diagram (FBD) to see why the net force is zero.  Skills to draw FBD are  essential in solving problems in statics.

Top book exerts -mg (downwards) on the middle book.

Middle book exerts -mg (downwards) on the bottom book.

Total downward force is -mg-mg = -2mg

By Newton's third law, when an object is not in motion, reaction equals action of -2mg in the opposite direction, therefore the reaction (upwards) is +2mg.

This makes the net force of -2mg (downwards) + 2mg (upwards) =0

On a horizontal table, three books are resting and balanced. The net force on the middle book will be equal to zero.

Equilibrium is the condition of an object when two or more opposing forces, whether internal, external or a combination of both, act on the body and cancel one another out to maintain the object in the same state as it was. The Latin term for weight or balance, libra, serves as the origin of the word equilibrium.

According to the question :

The net force is 0 if the middle book does not accelerate in any direction.

The Middle book is impacted negatively (downwards) by the top book.

The middle book pulls down on the lower book by -mg.

The total downward force is -2mg = (-mg-mg)

According to Newton's third rule, a reaction when an item is not moving equals an action of -2mg in the opposite direction, hence the reaction (upwards) is a response of +2mg.

Consequently, the net force of -2mg (downwards) + 2mg (upwards) = 0 is created.

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Answer:

D. ) The force would be zero newtons

Explanation:

Because

If you are at the center of the earth, gravity is zero because all the mass around you is pulling "up" (every direction there is up!)

So F=mg so if g is zero F is also zero

Answer:

Explanation:

magnetic field B = (3 i + 8 x 2 j )x 10⁻³ T

= (3 i + 16 j )x 10⁻³ T

L = - i ( unit length of conductor )

Force F = I ( L x B ) , I is current

= 5 [ - i x ( 3i + 16 j ) 10⁻³]

= 5 ( - 16 k ) x 10⁻³

F = - 80 x 10⁻³ k

Answer:

θ = 41.8º

Explanation:

This is an internal total reflection exercise, the equation that describes this process is

         sin θ = n₂ / n₁

where n₂ is the index of the incident medium and n₁ the other medium must be met n₁> n₂

        θ = sin⁻¹ n₂ / n₁

let's calculate

       θ = sin⁻¹ (1.00 / 1.50)

       θ = 41.8º

Answer:

Infrasound vs. Ultrasound: Infrasound is sound that is below the lower limit of human hearing, below 20 Hz, and ultrasound is above the upper limit of human hearing, above 20,000 Hz.  Individuals use infrasound - this recurrence run for checking seismic tremors and volcanoes, graphing rock and oil developments underneath the earth. Infrasound is described by a capacity to get around hindrances with little scattering.  

For instance, a few creatures, for example, whales, elephants and giraffes convey utilizing infrasound over significant distances. Torrential slides, volcanoes, seismic tremors, sea waves, water falls and meteors produce infrasonic waves. Symptomatic ultrasound, additionally called sonography or demonstrative clinical sonography, is an imaging technique that utilizes high-recurrence sound waves to create pictures of structures inside your body. The pictures can give important data to diagnosing and treating an assortment of ailments and conditions.

Explanation:

idk how many words this is but its a start for u to add on to and i hope this helps and its in my own words - pls mark me brainiest

Answer:

Ultrasound vs. Infrasound Research Exploration

Beyond the limit of human hearing, ultrasound is above 20,000 Hz. Under the limit of human hearing, infrasound is below 20 Hz. Individuals use infrasound - this recurrence run for checking seismic tremors and volcanoes as well as graphing rock and oil developments beneath the earth. Infrasound is described by a capacity to get around hindrances with little scattering.  

For instance, creatures like whales, elephants and giraffes convey utilizing infrasound over significant distances. Torrential slides, volcanoes, seismic tremors, sea waves, waterfalls and meteors produce infrasonic waves. Symptomatic ultrasound, additionally called sonography or demonstrative clinical sonography, is an imaging technique that utilizes high-recurrence sound waves to create pictures of structures inside your body. The pictures can give important data to diagnosing and treating an assortment of ailments and conditions.

(Not turned in yet, but this is what i have so far. Good luck 8th graders <33)

-Sav xx

Answer:

Options A, B as well as C are the correct choices.

Explanation:

This form of learning isn't always linked to the perhaps one given choice. And the response to the above will still be the appropriate one.