Stars that are not very hot but give off a lot of light are
O nebula
O main sequence stars
giants
O giants
O dwarfs

Answer:

 v = 220 m / s

Explanation:

This is a kinematics exercise, the expression for velocity is

          v = 25 t² - 80 t - 200

asks the velocity for time t = 6 s.

let's calculate

        v = 25 6² - 80 6 - 200

        v = 220 m / s

The velocity for the first six seconds when acceleration is zero is -44 m/s.

The velocity of an object is the rate of change displacement with time.

The velocity of the object for the first six seconds when the acceleration is zero is calculated as follows;

[tex]a = \frac{dv}{dt} \\\\a = 50t - 80\\\\0 = 50t - 80\\\\50t = 80\\\\t = 1.6 \ s[/tex]

Velocity when time = 1.6 s

[tex]v(1.6) = 25(1.6)^2 - 80(1.6) - 200\\\\v(1.6) = -264 \ m/s[/tex]

The velocity for the first six seconds when acceleration is zero.

[tex]v = v_{a =0} + v_6\\\\v = - 264 \ + 25(6)^2 - 80(6) - 200\\\\v = -44 \ m/s[/tex]

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Answer: 10,500 kg m/s

Explanation: (1,000 + 50)(10)

Answer:

Explanation:

The surface area of a star estimated by the energy emitted per sq meter yields the overall luminosity, which can be represented mathematically as:

[tex]L= 4 \pi R^2 \sigma T^4 --- (1)[/tex]

where;

L ∝ R²T⁴

and;

R = radius of the sphere

σ = Stefans constant

T = temperature

Also; The following showcase the relationship between flux density as well as illuminated surface area as:

[tex]F = \dfrac{L}{A}[/tex]

where

A = 4πd² and L ∝ R²T⁴

[tex]F = \dfrac{R^2T^4}{4 \pi d^2} \\ \\ F \alpha \dfrac{R^2T^4}{ d^2} --- (2)[/tex]

Given that:

distance d₁ = 20 pc

Then, using equation (2)

[tex]F_1 \ \alpha \ \dfrac{R^2_1T^4_1}{ d^2_1}[/tex]

However, we are also being told that there is a temp. drop by a factor of 3;

So, the final temp. [tex]T_2 = \dfrac{T_1}{3}[/tex]; and the final radius is [tex]R_2 = 100R_1[/tex] since there is increment by 100 folds.

Now;

[tex]F_2 \ \alpha \ \dfrac{R^2_2T^4_2}{ d^2_2}[/tex]

SInce;

[tex]F_1 = F_2[/tex]

It implies that:

[tex]\dfrac{R^2_1T^4_1}{ d^2_1 } = \dfrac{R^2_2T^4_2}{ d^2_2} \\ \\ d_2 = \sqrt{\dfrac{R_2^2T_2^4}{R_1^2T_1^4}}(d_1)[/tex]

Replacing all our values, we have:

[tex]d_2 = \sqrt{\dfrac{(100R_1)^2 \times (\dfrac{T_1}{3})^4}{R_1^2T_1^4}}(20 ) \\ \\ d_2 = \sqrt{\dfrac{(100)^2 }{3^4}}(20 ) \\ \\ d_2 = \sqrt{\dfrac{(100)^2 }{3^4}}(20 ) \\ \\ d_2 =222 \ pc[/tex]

Answer:

the time interval that an earth observer measures is 4 seconds

Explanation:

Given the data in the question;

speed of the spacecraft as it moves past the is 0.6 times the speed of light

we know that speed of light c = 3 × 10⁸ m/s

so speed of spacecraft v = 0.6 × c = 0.6c

time interval between ticks of the spacecraft clock Δt₀ = 3.2 seconds

Now, from time dilation;

t = Δt₀ / √( 1 - ( v² / c² ) )

t = Δt₀ / √( 1 - ( v/c )² )

we substitute

t = 3.2 / √( 1 - ( 0.6c / c )² )

t = 3.2 / √( 1 - ( 0.6 )² )

t = 3.2 / √( 1 - 0.36 )

t = 3.2 / √0.64

t = 3.2 / 0.8

t = 4 seconds

Therefore, the time interval that an earth observer measures is 4 seconds

Answer:

air

Explanation:

water is a liquid and can be refracted.

glass is a solid which can also be refracted.

however,

air you can't see just see mainly.

air is the answer.

hope this helps :)

true. true is the correct answer

Answer:

a. πi(r₁² + r₂²)

b. πi(r₂²- r₁²)

Explanation:

(a) Find the net dipole moment of this system.

The magnetic dipole moment, μ = iA where i = current and A = For area

For the circular loop with radius r₁, and current i₁ in a clockwise direction, i₁ = + i positive

μ₁ = i₁A₁

= +i(πr₁²)

= πir₁²

For the circular loop with radius r₂, and current i₂ in a clockwise direction, i₂ = +i

μ₂ = i₂A₂

= +i(πr₂²)

= πir₂²

The net dipole moment, μ = μ₁ + μ₂

μ = μ₁ + μ₂

=  πir₁² + πir₂²

= πi(r₁² + r₂²)

(b) Repeat for the reversed current in the inner loop

With the reversed current in the inner loop, the current is negative. So i₂ =-i

μ₁ = i₂A₁ = -i(πr₁²) = -πir₁²

So,

μ = μ₁ + μ₂

=  -πir₁² + πir₂²

= πi(-r₁² + r₂²)

= πi(r₂²- r₁²)

Answer:

garden

Explanation: All the other habitats are aquatic

Answer: C. Lithium

Explanation: Quizzed

C. Lithium has 1 valence electron in its outer shell and so will react with a  group 17 element in a 1:1 ratio.

The last number of group that an element belongs to on the periodic table tells the number of valence electrons that it will have.

Group 17 elements have seven valence electrons and so need one more to achieve stability which is why they will react with Lithium (which has that one electron) in a 1:1 ratio.

Some of those elements include:

In conclusion therefore, Lithium has 1 valence electron and will react with group 17 elements in a 1:1 ratio.

Find out more at https://brainly.com/question/20516188.

Answer:

earth , mercury , and neptune

Explanation:

pls mark brainless

Answer:

a)  

get mass of planet:  

ρ = M / V  

V = 4/3 * R_1^3  

M = ρ * V  

M = ρ * 4/3 * R_1^3  

equate force equations:

F = (GMm) / r^2     // r = R_2  

F = ma  

a = v^2/R_2  

F = m * (v^2/R_2)    

m * (v^2/R_2) = (GMm) / R_2^2  

plug in and solve v^2:  

m * (v^2/R_2) = (G * (ρ * 4/3 * R_1^3) *m) / R_2^2  

v^2 = (G * ρ * (4/3) * π * R_1^3) / R_2

put into kinetic energy equation:  

K = 1/2 * m * v^2  

K = 1/2 * m * (G * ρ * (4/3) * π * R_1^3) / R_2

B)

givens:  

U = -(GmM) / R_2

plug in mass of planet:  

U = -(G * m * ρ * 4/3 * R_1^3) / R_2

C)

use previous equations and do some algebra:

K/U = (1/2 * m * (G * ρ * (4/3) * π * R_1^3) / R_2) * -(R_2 / (G * m * ρ * 4/3 * R_1^3))  

K/U = -1/2

Answer:

The balloon will collapse

Explanation:

When air is removed from the bell jar, the balloon will collapse if the internal pressure from the balloon does not balance the atmospheric pressure from the surroundings.

Answer:

.0000004

Explanation:

The mass of a brick with a volume of 0.0006 m³ and a density of 1600 kg/m³ is 0.96kg.

The mass of a substance can be calculated by multiplying the density of the substance by its volume. That is;

Mass = density × volume

According to this question, the density of brick is 1,600 kg/m3 and it has a volume of 0.0006m³. The mass is calculated as follows:

Mass = 0.0006 × 1600

Mass = 0.96kg

Therefore, the mass of a brick with a volume of 0.0006m³ and a density of 1600 kg/m³ is 0.96kg.

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Question (Fill-In-the Blank):

As wavelength decreases the frequency of a wave _______​

Answer:

Increases

Explanation:

When waves travel from one medium to another the frequency never changes. As waves travel into the denser medium, they slow down and wavelength decreases. Part of the wave travels faster for longer causing the wave to turn. The wave is slower but the wavelength is shorter meaning frequency remains the same.

[tex] \boxed{ \boxed{ \huge\mathrm{Answer࿐}}}[/tex]

[tex] \mathrm{wavelength \: \: \dfrac{1}{ \propto} \: \: frequency }[/tex]

So, As wavelength decreases the frequency of a wave Increases.

_____________________________

[tex]\mathrm{ \#TeeNForeveR}[/tex]

Answer:

Pressure=Force/Area

F=50N

A= L x W

Change the units to metres

W= 0.2x10-³m

L= 12 x 10-²m

A= 0.2x10-³ x 12 x10-²

A=2.4x10^-5m²

P= 50/2.4x10^-5

= 2.08x10^6Nm-¹ ~ 2.1x10^6Nm-¹

Answer:

it is d, just did the quiz. all this came from the amazing com mentor who said a was wrong and it is d, thank you.

Explanation:

This splitting of the big atomic nucleus into smaller nuclei is known as nuclear fission, and further discussion is as follows:

The neutron collides with a uranium atom that splits during the fission of nuclear, producing a tremendous quantity of energy in the form of heat produced. If a uranium atom splits, additional neutrons are extricated.

Therefore, the final answer is "Option D".

Find out more about the nuclear fission here:

brainly.com/question/913303

Answer: 170km/hr to the South

Explanation:

The resultant velocity of the plane ilwill be gotten by adding the value of the velocities of the plane with the tallwind. It should be noted that the direction of the wind is.takwn into consideration.

Therefore, the resultant velocity of the plane will be:

= 20km/hr + 150km/hr

= 170km/hr to the South

Answer:

Resultant Velocity = 20 km/h + 150 km/h = 170 km/h

Explanation:

Answer:

so a man counts 6 waves on a pound in 10 second

Explanation:

6×10 = 60

60/40

so the answer is3

Answer

1) AlH3= trigonal planar

2) CH2F2= tetrahedral

3) PH3= trigonal pyramidal

4) O3= bent

Explanation:

I took the test

Answer:

Hello There!!

Explanation:

Work done= force × distance moved

Work done=5000N×15m

Work done=75,000J

hope this helps,have a great day!!

~Pinky~

Answer:

the vacoule in a plant is larger than that of an animal

Answer: i think it is for 16,  Infectious diseases commonly spread through the direct transfer of bacteria. for 17 i think In biology, immunity is the capability of multicellular organisms to resist harmful microorganisms. i dont have a clue about the others but i hope this is right or atleast helps

Explanation:

Answer:

this pattern to occur there must be coherence in the light beams.

you use a flashlight, the rays are incoherent so diffraction patterns cannot occur.

Explanation:

The point pattern that appears in the wall is the result of the interference and diffraction processes through each space of the mesh, for this pattern to occur there must be coherence in the light beams.

The coherence process is that all the rays have the same constant and phase, before the appearance of the lasers, the light is stopped by a small opening and this ray is the one that passes through the slits, with the appearance of the laser this it is consistent from its production process, so opening is not necessary, with this there is much greater intensity and the measurement process is simplified.

When you use a flashlight, the rays are incoherent so diffraction patterns cannot occur.

Polarization has no effect on diffraction patterns so it does not matter if it is vertical or horizontal.

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Explanation:

Answer:

hello how are you

have a great day

Answer:

Friendships can have a major impact on your health and well-being, but it's not always easy to build or maintain friendships. Understand the importance of friendships in your life and what you can do to develop and nurture friendships

Answer:

angular velocity = 2.6543 rad/s

Explanation:

To find the angular velocity of the wheel when the disk moves to the right 0.5 ft, we need to be aware that the spring will stretch twice the value of gyration with any slight change in the position or movement of gyration since the top of the wheel is holding the spring.

The work done here:

= ((distance moved by the wheel) X spring constant X (Final displacement^2 - Initial displacement^2)) + Mass (q2 – q1)

Where q2 = 0.5ft

            q1 = 0.8 lb      

Note that linear velocity = radius X angular velocity

= -0.5(10)(1^2 – 0) + 15(0.5/0.8) = 4.375 ft·lb    

Then, the kinetic energy :

 Since the spring is initially unstretched, the initial tension in the spring = 0

So the final tension = ((distance moved by the wheel) X (linear velocity)^2 X (angular velocity) ^2 + (distance moved by the wheel) X (linear velocity) X ( radius of gyration) ^2 X (angular velocity) ^2

= 0.5(40/32.2)(0.8w) ^2 + 0.5(40/32.2)(0.6)^2 X w2

final tension = 0.621 w2

So the angular velocity of the wheel when disk moves to the right 0.5 ft = The Initial workdone + Initial kinetic energy will be equal to the final workdone + the final Kinetic energy

0 + 4.375 ft·lb = 0.621 w2

 angular velocity = 2.6543 rad/s

Answer:

Explanation:

I dont  have an explenation    

Answer:

The pressure before expansion is 717.1 kPa.

Explanation:

We need to use the Ideal Gas equation to find the initial pressure:

[tex] PV = nRT [/tex]

Where:

P: is the pressure

V: is the volume

n: is the number of moles

R: is the gas constant

T: is the temperature

Since the number of moles does not change after the expansion, we need the following number of moles:

[tex] n = \frac{P_{f}V_{f}}{RT_{f}} [/tex]  (1)

Where "f" is for final

Before the expansion, the pressure is:

[tex] P_{i} = \frac{nRT_{i}}{V_{i}} [/tex]   (2)

By entering equation (1) into (2) we have:

[tex] P_{i} = (\frac{P_{f}V_{f}}{RT_{f}})(\frac{RT_{i}}{V_{i}}) [/tex]

[tex]P_{i} = \frac{P_{f}V_{f}T_{i}}{T_{f}V_{i}} = \frac{900 kPa*900 cm^{3}*292.15 K}{550 K*600 cm^{3}} = 717.1 kPa[/tex]

Therefore, the pressure before expansion is 717.1 kPa.                  

I hope it helps you!        

Answer:

I would say d I had the same question yesterday and I got it correct so hope that helps