What has to happen for a star to join the main sequence ?

1) Nuclear Fusion

2) Shell Heating

3) Use up most of its available fuel

4) Hydrostatic Equilibrium

Answers

Answer 1

Answer:

Nuclear fusion

Explanation:

This is because main sequence of star is powered by fusion of hydrogen to helium atoms together and this process releases energy. The energy released when the gas collapse into a protostar make the center of the protostar to be extremely hot. When the core becomes very hot, nuclear fusion can start.


Related Questions

The type of brightness in which all
stars being observed are the same
distance from Earth is known as
which type of brightness?
A. absolute brightness.
B. apparent brightness.
C. obvious brightness.
D. compositional brightness.

Answers

the answer is C . obvious brightness

Determine the potential difference between the ends of the wire of resistance 5 Ω if 720 C passes through it per minute.

Answers

Answer:

The potential difference between the ends of a wire is 60 volts.

Explanation:

It is given that,

Resistance, R = 5 ohms

Charge, q = 720 C

Time, t = 1 min = 60 s

We know that the charge flowing per unit charge is called current in the circuit. It is given by :

I = 12 A

Let V is the potential difference between the ends of a wire. It can be calculated using Ohm's law as :

V = IR

V = 60 Volts

So, the potential difference between the ends of a wire is 60 volts. Hence, this is the required solution.

PLEASE HELP ME PLEASE!​

Answers

Answer:

40N

Explanation:

The weight is "how much force of gravity drags this down".

Because we're told that gravity on the Moon exerts 1.6N of force per kg, a 25kg object will weigh:

[tex]F_g = 25kg \cdot 1.6\frac{N}{kg} = 40N[/tex]

3. A person is pushing a box down the hallway with a force of 25N. The Force of friction is 15N
a. List all of the forces on the box (use pushing/pulling on

Answers

Answer:

10 N

Explanation:

Given that,

Force applied by a person = 25 N

Force of friction = 15 N

The net force acting on the box is given by :

F = Applied force - the force of friction

So,

F = 25 N - 15 N

F = 10 N

So, the required force is equal to 10 N.

What is the
mass
density
of an object of
equal to 100 grams and volume of 20 cubic
centimeter​

Answers

Answer:

[tex]d=5\ g/cm^3[/tex]

Explanation:

Given that,

Mass of the object, m = 100 grams

Volume of the object, V = 20 cm³

We need to find the density of the object. We know that, density is equal to mass per unit volume. So,

[tex]d=\dfrac{m}{V}\\\\d=\dfrac{100\ g}{20\ cm^3}\\\\d=5\ g/cm^3[/tex]

So, the density of the object is equal to [tex]5\ g/cm^3[/tex].

1.00 x 100 kg of clear liquid (specific heat
capacity = 5.11 x 102 J/kg•°C) at a temperature
of 15.0°C gains 3.33 x 10 J of heat. What is the
final temperature of the liquid? (Assume the
melting point is less than 15.0°C and the boiling
point is greater than 62.0°C.)

Answers

Answer:

No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a ... to change 1 kg of liquid water at the normal boiling point (100ºC at atmospheric pressure) to steam (water vapor).

The melting point of lead is 327.3o C. Assume the final temperature of the system is T. Then the amount of energy released by the lead as it solidifies is. ΔQ = mleadLlead = 0.09 kg*(2.45*104 J/kg) = 2205 J

Lee and Leigh are twins. At their first birthday party, Lee is placed on a spaceship that travels away from the earth and back at a steady 0.714 c . The spaceship eventually returns, landing in the swimming pool at Leigh's eleventh birthday party. When Lee emerges from the ship, how old is he?

a. He is still only 1 year old
b. He is 8 years old
c. He is also 11 years old
d. He is 18 years old

Answers

Answer:

b. He is 8 years old

Explanation:

We will use Einstein's formula for time dilation, to calculate the age of Lee. Because Lee was traveling comparable to the speed of light, his age must be lesser than Leigh.

[tex]T = \frac{T_o}{\sqrt{1-\frac{v^2}{c^2} } }[/tex]

where,

T₀ = Time on Earth = ?

T = Relative Time = 10 years

v = relativistic speed of Lee = 0.714 c

c = speed of light = 3 x 10⁸ m/s

Therefore,

[tex]10\ years = \frac{T_o}{\sqrt{1-\frac{(0.714\ c)^2}{c^2} } } \\\\[/tex]

T₀ = 7 years

Hence, the age of Lee will be:

[tex]Lee's\ Age = 1\ year + 7\ years = 8\ years[/tex]

b. He is 8 years old

A 0.017-kg acorn falls from a position in an oak tree that is 18.5 meters above the ground. Calculate the velocity of the acorn just before it reaches the ground (rounding your answer to the integer) and its kinetic energy when hitting the ground (rounding your answer to the nearest tenth).

Answers

Answer:

The velocity and translational kinetic energy of the acorn when hitting the ground are approximately 19 meters per second and 3 joules, respectively.

Explanation:

Let suppose that the acorn is a conservative system. By Principle of Energy Conservation, we understand that initial potential gravitational potential energy ([tex]U_{g}[/tex]), in joules, which is related to initial height above the ground, is equal to the final translational kinetic energy ([tex]K[/tex]), in joules, related to the instant just before hitting the ground. Let suppose that ground has a height of zero. That is:

[tex]U_{g} = K[/tex] (1)

[tex]m\cdot g \cdot h = \frac{1}{2}\cdot m \cdot v^{2}[/tex] (1b)

Where:

[tex]m[/tex] - Mass, in kilograms.

[tex]g[/tex] - Gravitational acceleration, in meters per square second.

[tex]h[/tex] - Height, in meters.

[tex]v[/tex] - Speed, in meters per second.

If we know that [tex]m = 0.017\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex] and [tex]h = 18.5\,m[/tex], then the velocity and the translational kinetic energy of the acorn just before hitting the ground is:

[tex]m\cdot g \cdot h = \frac{1}{2}\cdot m \cdot v^{2}[/tex]

[tex]v = \sqrt{2\cdot g \cdot h}[/tex]

[tex]v \approx 19.049\,\frac{m}{s}[/tex]

[tex]K = \frac{1}{2}\cdot m\cdot v^{2}[/tex]

[tex]K = 3.084\,J[/tex]

The velocity and translational kinetic energy of the acorn when hitting the ground are approximately 19 meters per second and 3 joules, respectively.

PLEASE HELP, PLEASE A CORRECT ANSWER!​

Answers

Answer: I like your profile picture

Explanation:

what mass of water is required to absorb 4.7 x 10 to the 5th power J of energy from a car engine while the temperature increases from 298K to 355 K


HELPPPPP

Answers

I would answer but the other guy got here first and I don’t know the answer sorry

form
bonds with each other.
There are many kinds of mixtures. Some mixtures are
chunky like a mixture of peanuts and raisins. These
mixtures are called
I
mixtures.

Answers

Answer:

Homogeneous mixtures

Explanation:

I think so because homogeneous means mixed mixtures

The Image shows a magnetic field around the poles of a magnet. Identify the areas where the magnetic force is the strongest.
N

Answers

Answer:

strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.

Explanation:

The lines of magnetic force are drawn so that the density of lines is proportional to the intensity of the magnetic field.

Therefore, the sections where the magnetic field is strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.

PLEASE HELP!

how am i supposed to label a graph using the points from the protractor?

Answers

Answer:

srghgddggjjjkkkk

Explanation:

fhhgxxxxxxxx3

errghydhi

list some application of atmospheric pressure?​

Answers

Answer:

Drinking straw, syringe, Dropper, vacuum, etc.

Explanation:

Determine the volume of the ring/tube using Archimedes' Principle and compare your results to the volume of the ring/tube calculated from physical measurements. Do not tie the thread directly to the balance; use the paper clip as a hook. Assume that the density of the water is 1.0 g/cm. Neatly show all work and provide all necessary data. If the TA cannot duplicate your results from the data that you provide, your score will be drastically reduced.
Volume of ring/tube via Archimedes' Principle (A): ___________
Volume of ring/tube via Physical Measurement (B): __________
Percent Difference-=(A-B)/ (A+B)/2 x100%-=_________
Percent Difference <-3% <-5% <= 10% <--15% <-20% | >20%
Points 50 45 40 25 10 0

Answers

Answer:fuafnshf dj en jz

Explanation:

Can. Nd I do j dj cdj an man Jaz jxn nah an b

4 points
Bonus: We know that a huge star went supernova in our area a long time
ago because of the large amount of
on earth.
Water
Oxygen
Iron
Carbon

Answers

Answer: i may not be 100% accurate but i believe it is iron, there is a fire work that uses iron to shine a certain way and is found on stars.

What is the approximate size of the Earth's magnetic field? (dont ask me to specify thats what the question is and im as confused as heck too)

Answers

Answer:

The Earth's magnetic field intensity is roughly between 25,000 - 65,000 nT (.25 -.65 gauss).

Explanation:

To measure the Earth's magnetism in any place, we must measure the direction and intensity of the field. The Earth's magnetic field is described by seven parameters. These are declination (D), inclination (I), horizontal intensity (H), the north (X), and east (Y) components of the horizontal intensity, vertical intensity (Z), and total intensity (F). The parameters describing the direction of the magnetic field are declination (D) and inclination (I). D and I are measured in units of degrees, positive east for D and positive down for me. The intensity of the total field (F) is described by the horizontal component (H), vertical component (Z), and the north (X) and east (Y) components of the horizontal intensity. These components may be measured in units of gauss but are generally reported in nanoTesla (1nT * 100,000 = 1 gauss). The Earth's magnetic field intensity is roughly between 25,000 - 65,000 nT (.25 - .65 gauss). Magnetic declination is the angle between magnetic north and true north. D is considered positive when the angle measured is east of true north and negative when west.  The magnetic inclination is the angle between the horizontal plane and the total field vector, measured positive into Earth. In older literature, the term “magnetic elements” is often referred to as D, I, and H.

Two long current-carrying wires run parallel to each other and are separated by a distance of 5.00 cm. If the current in one wire is 1.65 A and the current in the other wire is 3.25 A running in the opposite direction, determine the magnitude and direction of the force per unit length the wires exert on each other.

Answers

Answer:

The magnitude of the force per unit length is 2.145 x 10⁻⁵ N/m and the direction of the force is outward or repulsive since the current in the two parallel wires are flowing in opposite direction.

Explanation:

Given;

distance between the parallel wires, r = 5.0 cm = 0.05 m

current in the first wire, I₁ = 1.65 A

current in the second wire, I₂ = 3.25 A

The magnitude of the force per unit length between the two wires is calculated as follows;

[tex]\frac{F}{l} =\frac{\mu_0 I_1 I_2}{2\pi r} \\\\\frac{F}{l} =\frac{4\pi \times 10^{-7} \times 1.65 \times 3.25}{2\pi \times 0.05} \\\\\frac{F}{l} = 2.145 \times 10^{-5} \ N/m[/tex]

Therefore, the magnitude of the force per unit length is 2.145 x 10⁻⁵ N/m and the direction of the force is outward or repulsive since the current in the two parallel wires are flowing in opposite direction.

A ray of light is incident from air on the surface of a block of clear ice (nice=1.31) at an angle of 45.0° with the normal. Part of the light is reflected and part is refracted. Find the angle between the reflected and refracted light.

Answers

Answer:

A ray of light is incident from air on the surface of a block of clear ice (nice=1.31) at an angle of 45.0° with the normal. Part of the light is reflected and part is refracted. Find the angle between the reflected and refracted light.

Help please due tomorrow

Answers

Hope this helps!!!!

When the electrons reach the collector, they flow towards the positivly charged grid. The resulting current is measured. Note that as the electrons accelerate from the cathode toward the grid, they collide with the mercury atoms. Assume that these collisions are completely elastic. How does the collected current vary if the ΔVgridΔVgrid is slowly increased? View Available Hint(s)

Answers

Answer:

We can conclude by saying that in the beginning current will increase but after sometime, it becomes saturated.

Explanation:

Note: No information on change in number of electron generated.

Since there is a collision, the electrons emitted will not reach the collector at same time. As the voltage is increased, the the speed with which the electrons will reach the collector starts to increase. Due to this, electric current will first increases till all the emitted electrons reach the collector. Since we are not provided with the information that number of electrons generated are changing, after increasing voltage current will increase for some time and then reaches a saturated state.

We can conclude by saying that in the beginning current will increase but after sometime it becomes saturated.

Just as optical astronomers observe the visible light emitted by objects such as stars and galaxies, radio astronomers can also observe the radio waves emitted by these objects, as well as the radio waves emitted by gas and dust. However, radio telescopes are different from optical telescopes in important ways. In general, compared to optical telescopes, radio telescopes are larger. more curved. more expensive. smaller. This is because

Answers

Answer:

Radio telescopes are LARGER than optical telescopes and this is because radio wavelengths  are much longer than optical wavelengths

Explanation:

In general radio telescopes are LARGER than optical telescopes and this is because radio wavelengths  are much longer than optical wavelengths.

The main difference between radio telescopes and other telescopes especially optical telescopes is based on size and wavelength of both telescopes  

uest
1. State Newton's law of cooling.​

Answers

Answer:

Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its surroundings. The law is frequently qualified to include the condition that the temperature difference is small and the nature of heat transfer mechanism remains the same. As such, it is equivalent to a statement that the heat transfer coefficient, which mediates between heat losses and temperature differences, is a constant. This condition is generally met in heat conduction (where it is guaranteed by Fourier's law) as the thermal conductivity of most materials is only weakly dependent on temperature. In convective heat transfer, Newton's Law is followed for forced air or pumped fluid cooling, where the properties of the fluid do not vary strongly with temperature, but it is only approximately true for buoyancy-driven convection, where the velocity of the flow increases with temperature difference. Finally, in the case of heat transfer by thermal radiation, Newton's law of cooling holds only for very small temperature differences.

When stated in terms of temperature differences, Newton's law (with several further simplifying assumptions, such as a low Biot number and a temperature-independent heat capacity) results in a simple differential equation expressing temperature-difference as a function of time. The solution to that equation describes an exponential decrease of temperature-difference over time. This characteristic decay of the temperature-difference is also associated with Newton's law of cooling

FREE BRAINIEST IF YOU ANSWER THIS


How long must a 400 W electrical engine work in order to produce 300 kJ of work?

Answers

The watt is a rate, similar to something like speed (miles per hour) and other time-interval related measurements.

Specifically, watt means Joules per Second. We are given that the electrical engine has 400 watts, meaning it can make 400 joules per second. If we need 300 kJ, or 3000 Joules, then we can write an equation to solve the time it would take to reach this amount of joules:

w * t = E

w: Watts

t: Time

E: Energy required

(Watts times time is equal to the energy required)

Input our values:

400 * t = 3000

(We need to write 3000 joules instead of 300 kilojoules, since Watts is in joules per second. It's important to make sure your units are consistent in your equations)

Divide both sides by 400 to isolate t:

[tex]\frac{400t}{400}[/tex] = [tex]\frac{3000}{400}[/tex]

t = 7.5 (s)

It will take 7.5 seconds for the 400 W engine to produce 300 kJ of work.

If you have any questions on how I got to the answer, just ask!

- breezyツ

The 400 W electrical engine must work for 12 minute 30 second in order to produce 300 kJ of work.

What is power?

The quantity of energy moved or converted per unit of time is known as power in physics. The watt, or one joule per second, is the unit of power in the International System of Units. Power is also referred to as activity in ancient writings. A scalar quantity is power.

Power of the electrical engine = 400 Watt.

Work done by the electrical energy = 300 kJ

= 300 × 1000 Joule

= 300000 Joule.

Now from the definition of power:

Power = Work done/time interval

Hence, required time interval = work done/ power

= 300000 Joule/400 watt

= 750 second

= 12 minute 30 second.

Hence,  a 400 W electrical engine must work for 12 minute 30 second in order to produce 300 kJ of work.

Learn more about power here:

https://brainly.com/question/29575208

#SPJ2

HELP!!!!

A student did an experiment to determine the
specific heat capacity of an unknown metal.
She heated 1.00 x 10- kg of the metal to 225°C
and quickly placed it in an insulated container
(negligible specific heat capacity) that contained
0.0900 kg of water at a temperature of 18.0°C.
What is the final temperature of the water if the
specific heat capacity of the metal is
2.11 x 102 J/kg.°C?

Answers

Answer:

T₂ = 16.83°C

Explanation:

Applying the law of conservation of energy principle here in this situation we get the following equation:

[tex]Energy\ Lost\ by\ Metal = Energy\ Gaine\ by\ Water\\m_{metal}C_{metal}(T_2-T_{1metal}) = m_{w}C_{w}(T_2-T_{1w})[/tex]

where,

T₂ = Final Temperature of Water = Final Temperature of Metal = ?

C_metal = Specififc Heat Capacity of the metal = 2.11 x 10² J/lg.°C

T_1metal = Initial Temperature of Metal = 225°C

m_metal = mass of metal = 1 x 10⁻²[tex](0.01\ kg)(211\ J/kg.^oC)(T_2-225^oC) = (0.09\ kg)(4184\ J/kg.^oC)(T_2-18^oC)\\2.11 T_2 - 474.75 = 376.56T_2 - 6778.08\\374.45T_2 = 6303.33\\[/tex] kg (exponent assumed due to missing info in question)

C_w = Specififc Heat Capacity of the water = 4184 J/lg.°C

T_1w = Initial Temperature of water = 18°C

m_w = mass of water = 0.09 kg

Therefore,

[tex](0.01\ kg)(211\ J/kg.^oC)(T_2-225^oC)=(0.09\ kg)(4184\ J/kg.^oC)(T_2-18^oC)\\\\2.11 - 474.75T_2 = 376.56 - 6778.08T_2\\[/tex]

T₂ = 16.83°C

Please Help with this

Answers

Answer: c is correct

Explanation: i did this

The scanning process and magnetic lenses used in a scanning electron microscope often results in fair to poor resolution and "fuzzy" images.
(A)True
(B)False

Answers

Answer:

(B)False is the answer.

Explanation:

Jill doubled the force acting on an object, yet she kept the acceleration constant or unchanged.
How did she do this?

Answers

Answer:

Mass doubles

Explanation:

Since F = ma, and given that the acceleration stayed constant, the mass must have changed. (Assuming thatt when the problem states the force doubles, they mean the net force doubles). Note, that the mass does not have to change if the acceleration is zero.

How much kinetic energy does a 0.30-kg stone have if it is thrown at 44 m/s?
O 440J
O 510 J
O 580J
0 290

Answers

Answer:

0 290

Explanation:

Answer:

290

Explanation:

the reason is that the formula for kinetic energy is half m×v².

you divde half by 0.30 multiply by 44×44

you get 290.4

then you round it to significant figures to get 290

example of kinetic energy into heat energy

Answers

Answer:

The kinetic energy of large objects can be converted into this thermal energy.

Explanation:

For example, if you drop a water balloon onto the ground, its kinetic energy is converted mostly to thermal energy. If the balloon weighs 1 kilogram and you drop it from about 2 meters, it will heat up by less.

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