Most stars are main-sequence stars, a group of stars for which size, mass, surface temperature, and radiated power are closely related. The sun, for instance, is a yellow main sequence star with a surface temperature of 5800 K. For a main-sequence star whose mass M is more than twice that of the sun, the total radiated power, relative to the sun, is approximately P/Psun = 1.5(M/Msun)3.5. The star Regulus A is a bluish main-sequence star with mass 3.8Msun and radius 3.1Rsun. What is the surface temperature of Regulus A?

Answer:

[tex]\frac{T_2}{T_1} = 1[/tex]

Explanation:

The root mean square velocity of the gas at an equilibrium temperature is given by the following formula:

[tex]v = \sqrt{\frac{3RT}{M} }[/tex]

where,

v = root mean square velocity of molecules:

R = Universal Gas Constant

T = Equilibrium Temperature

M = Molecular Mass of the Gas

Therefore,

For T = T₁ :

[tex]v = \sqrt{\frac{3RT_1}{M} }[/tex]

For T = T₂ :

[tex]v = \sqrt{\frac{3RT_2}{M} }[/tex]

Since both speeds are given to be equal. Therefore, comparing both equations, we get:

[tex]\sqrt{\frac{3RT_1}{M} }=\sqrt{\frac{3RT_2}{M} }\\\\\frac{T_2}{T_1} = 1[/tex]

Answer:

Explanation:

Kinetic energy of satellite = 1/2 m v²

= .5 x 1110 x 3.55²

= 6994.39 J

This energy comes from the elastic energy of  compressed spring

elastic energy = 1/2 k d² where k is elastic constant and d is compression in spring .

1/2 k d²  = 6994.39 J

kd² = 13988.77 --------------------------- (1)

force created by spring = k d

acceleration = force / mass

= k d / 1110

Given ,

k d / 1110  = 5 x g = 5 x 9.8 = 49

kd = 54390  ------------------------------------------------- ( 2 )

dividing ( 1 )  and ( 2 )

d =  13988.77 / 54390

= .25719 m

= 25.72 cm

kd = 54390

k x .25719 m = 54390

k = 211477.9 N /m

Optimal Arousal theory  focuses on finding the right level of stimulation.

William James (1842–1910), frequently referred to as the father of psychology in the United States, made significant contributions to early studies on motivation.

James proposed a number of instincts that help with survival as the driving forces behind conduct . An instinct is a species-specific pattern of behavior that is not taught, according to biology.

But there was a lot of disagreement over what exactly constitutes instinct among James's contemporaries. James postulated a number of unique human instincts, although many of his contemporaries had different lists.

Therefore, Optimal Arousal theory  focuses on finding the right level of stimulation.

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Answer:

a. The final speed , v' when it returns is the same speed, u as when it was released. v' = u

b. The time of flight T equals twice the time taken to reach the highest point, t. T = 2t

Explanation:

(a) As long as you can neglect the effects of the air, if you throw anything vertically upward, it will have the same speed when it returns to the release point as when it was released.

Using v² = u² - 2gh, we find the maximum height the object reaches. With u = initial vertical velocity, v = velocity at maximum height = 0 m/s (since it momentarily stops), g = acceleration due to gravity and h = maximum height

So, v² = u² - 2gh

0² = u² - 2gh

0 = u² - 2gh

-u² = -2gh

h = -u²/-2g

h = u²/2g

On its return trip to the point where it is released, the distance covered is h and its initial velocity u' = 0

With v' as the final velocity, we use

v'² = u'² + 2gh

substituting the values of the variables into the equation, we have

v'² = 0² + 2g(u²/2g)

v'² = 0² + u²

v'² = u²

taking square-root of both sides, we have

√v'² = √u²

v' = u

So, the final speed , v' when it returns is the same speed u as when it was released. v' = u

(b) The time of flight will be twice the time it takes to get to its highest point.

At the highest point, its velocity is zero.

Using v = u - gt where u = initial velocity, v = final velocity(velocity at highest point) = 0 (since it is momentarily at rest), g = acceleration due to gravity and t = time taken to reach the highest point.

So, substituting the values of the variables into the equation, we have

v = u - gt

0 = u - gt

-u = -gt

t = u/g

On its return trip, since we know its final velocity = u and its initial velocity is  0 m/s, again, using

v' = u' + gt' where u' = initial velocity = 0 (since it is at its highest point), v' = final velocity = u (velocity on return to release point), g = acceleration due to gravity and t' = time taken to reach release point from highest point

So, substituting the values of the variables into the equation, we have

v' = u' + gt'

u = 0 + gt'

u = gt'

t' = u/g = t

So, the time of flight, T = time taken to reach highest point + time taken to return to release point

T = t + t'

T = u/g +u/g

T = 2u/g

T = 2t

So, the time of flight T equals twice the time taken to reach the highest point, t. T = 2t

a) The average velocity at 4s is 12 m/s

b) The instantaneous velocity at t= 6s is 12 m/s

c) The average acceleration is; 12  - 0/ 4 - 0 n= 3 m/s^2

d) The time for the race is 10 s

We know that the velocity time graph is the kind of set up that has two axis and we can be able to use it to be read off the velocity of the acceleration  of the object. I would want us to recall  that the acceleration is the rate of change of the velocity of the object with time.

Now we have that;

The graph for the velocity of the object can be obtained by looking at the image that has been shown and then we read off the points that are on the graph. The  vertical axis shows the velocity of the graph while the horizontal axis shows the time that is covered in the graph.

The acceleration would be the ratio of the change in the velocity to the change in the time of the object.

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The law of motion that accounts for an apple accelerating as it falls from a tree is the law of gravity, specifically Newton's Second Law of Motion.

Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In the case of an apple falling from a tree, the net force acting on it is the gravitational force pulling it toward the Earth. The acceleration of the apple is therefore determined by the strength of this gravitational force and the mass of the apple.

As the apple falls from the tree, it accelerates toward the ground due to the gravitational force acting on it. The faster the apple falls, the greater its acceleration. This acceleration is commonly referred to as acceleration due to gravity, which is a constant value of 9.81 m/s^2 near the surface of the Earth.

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Answer:

1- Electric charges (positive and negative) - Benjamin Franklin  in 1742.

2- Coulomb's law: Charles Augustin Coulomb from 1764 to 1772.

3- Electric field:    Michael Faraday -  1821

4- Gauss's Law: Joseph Louis Lagrange was the first to formulate the rule in 1773, followed by Carl Friedrich Gauss in 1867.

Explanation:

The Electric charge: In 1742, an American orator and inventor named Benjamin Franklin designed the positive and negative values of the charge.

Coulomb's law: The theory was first published in 1785 by Charles Augustin de Coulomb, a French physicist who was instrumental and prominent in the advancement of electromagnetism theory.

Gauss Law: Carl Friedrich Gauss developed this law in 1835. It was not released until 1867, However, Classical electrodynamics is based on this law.

The horizontal distance travelled by the box is 143 m.

The horizontal distance travelled by the box is calculated by determining the time of motion of the box and the horizontal velocity of the airplane.

The time of motion of the box from the vertical height in which it was dropped is calculated as follows;

h = vt + ¹/₂gt²

where;

h = 0 + ¹/₂gt²

t = √ ( 2h / g )

t = √ ( 2 x 40 / 9.8 )

t = 2.86 seconds

The horizontal distance travelled by the box is calculated as follows;

d = Vₓ t

where

d = ( 50 m/s ) x ( 2.86 s )

d = 143 m

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The complete question is below;

A box is dropped out of a moving airplane. The airplane is traveling at 50m/s East. The box is dropped from rest with respect to the airplane. The box travels a vertical distance of 40 m before landing on a trampoline. The airplane continues traveling at a constant speed after the box is dropped and the wind resistance on the falling box is negligible. Find the horizontal distance travelled by the box.

A horizontal force of 10.0 N is acting on a 10 kg box that is sliding to the right along the floor with velocity v.

Most people make the common assumptions of rigid body action and ignoring air resistance and friction. In statics, all forces and moments must balance to zero; if they don't, the body is accelerating and the laws of statics do not apply, according to the physical interpretation.

The specific situation and the presumptions used will determine how many forces and moments are displayed. Most people make the common assumptions of rigid body action and ignoring air resistance and friction.

In statics, all forces and moments must balance to zero; if they don't, the body is accelerating and the laws of statics do not apply, according to the physical interpretation. The resultant forces and moments in dynamics can have non-zero values.

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Answer:

B) mass of pendulum bob

The addition of two sound waves produces a new wave of higher amplitude if their compressions and refractions line up. It is also known as constructive interference.

Interference can be described as a phenomenon in which two waves combine by adding at every single point in space and time, to form a resultant wave of greater or lower amplitude.

Constructive and destructive interference occurs in the interaction of waves that are correlated with each other because they come from the same source.

When two sound waves propagate in the same direction in phase with each other, their amplitude gets added, and the resultant wave is produced from constructive interference.

When two waves interfere with each other and have a displacement in the opposite direction.  When a crest of a wave meets the trough of another wave, the waves undergo destructive interference.

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The points in order of increasing value of the velocity can be ranked as:

B < C < A ≡ F < E < D.

The rate at which a body's displacement changes in relation to time is known as its velocity. Velocity is a vector quantity with both magnitude and direction. SI unit of velocity is meter/second.

According to the figure:

The points in order of increasing value of the velocity can be written as:

B < C < A ≡ F < E < D.

As the displacement becomes from positive to negative near point B, it has the lowest velocity and  as the displacement becomes from negative to positive near point D, it has the highest velocity

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Answer:

the answer is 2.6409.

Explanation:

i asked my teacher

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

There are two forces which are being balanced :

(Ⅰ) The force of gravity which is pushing the ping-pong ball downwards.

(Ⅱ) The force of the air that's coming from hairdryer which is pushing ping-pong ball upwards.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

Answer:

The power is 57.6 watts

Explanation:

We can use the Electric Power Equation to evaluate the power.

Electric Power Equation

[tex]P=IV[/tex]

[tex]P[/tex] is the power in watts

[tex]I[/tex] is the current in amps

[tex]V[/tex] is the voltage in volts

Our lightbulb has current of 0.480 A and a voltage of 120.0 V.

[tex]I=0.480\\V=120.0[/tex]

Now we can evaluate power.

Substitute our values in for the variables.

[tex]P=0.480*120[/tex]

[tex]P=57.6[/tex]

Answer:

e. none of the above

Explanation:

The frequency of an oscillating pendulum is the number of oscillation per unit time.

Mathematically, the frequency of an oscillating pendulum is given by the formula;

F = 1/2π√(k/m)

Where;

F is the frequency of oscillation.

k is the spring constant.

m is the mass of the spring.

Hence, none of the changes mentioned will increase the frequency of an oscillating pendulum.

The reaction is in A in vertical direction is W(2cosϕsinθ−sinϕcosθ)/2sin(θ−ϕ).

In terms of psychology, "stress" and "strain" are sometimes used interchangeably in popular culture, as in the expressions "I'm feeling stressed" or "I'm under a lot of pressure."

In engineering, these phrases have specific, technical meanings. If a hook in the steel wire is attached,

If you hang the wire from the ceiling while placing a weight on the lower end, it will sag. By dividing the length change by the starting length, the strain in the wire may be computed.

Thus, as per the given scenario, W(2cosϕsinθ−sinϕcosθ)/2sin(θ−ϕ) will be the equation.

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Answer:

An aqueous stagnant layer that overlies the apical membrane and the subepithelial blood flow are potential barriers to the absorption of drugs that readily penetrate the absorbing cell of the epithelium. The apical, basal, and basement membranes are potential barriers to the absorption of less permeable drugs.

claiming points because question is old + no keywords in title

The things that I will need to survive the layer of the earth called the mesosphere would be thick clothings.

The five(5) layers of the earth include the following such as:

The Mesosphere is one of the layers of the earth that is found directly above the stratosphere and then below the thermosphere.

The characteristics of the mesosphere is that the temperature rises due to reduced absorption of solar radiation and increased cooling by CO2 radiative emissions.

Therefore, for an individual to survive and live effectively at the Mesosphere layer of the earth, such needs thick clothings.

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Answer:

C

Explanation:

The number of excess electrons is 4.0 x 107 Coulombs divided by 1.60 x 10-19 Coulombs, which is 2.5 x 1026 electrons.

Electrons are particles of matter that carry a negative electrical charge. Electrons are the smallest particles in the atom and are responsible for most of the atom's mass. Electrons orbit around the nucleus of the atom and are held together by the electromagnetic force. Electrons have a property called spin, which can have a value of either +1/2 or -1/2. Electrons are found in all elements and are important in chemical reactions as they are able to move around and form bonds with other atoms. Electrons are also important in electricity and magnetism.

The number of excess electrons on the balloon is equal to the charge of the balloon divided by the charge of an electron. Since the charge of an electron is 1.60 x 10-19 Coulombs, the number of excess electrons is 4.0 x 107 Coulombs divided by 1.60 x 10-19 Coulombs, which is 2.5 x 1026 electrons.

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Answer: Flow rate 1670 cm³/s

Explanation:   Cross section  A =  π · (2 cm)²  = 12.56 cm²

                     V = 1000 l   , t = 10 min = 600 s

                       dV / dt = 1000 l / 600 s = 1,67 l/s = 1670 cm³ /s

                      That was not asked,

                   dV / dt = vA  and flow speed v = (dV/dt)/A = 133 cm/s

Answer:

p/2

Explanation:

Answer:

2 nitrogen and 1 oxygen,

Explanation:

N2=2 nitrogen

O= a single element

Answer:

The power will be "2.08 D".

Explanation:

According to the question,

The location of the image form lens,

[tex]d_i=50-2[/tex]

    [tex]=48 \ cm[/tex]

We know that,

⇒ [tex]\frac{1}{d_i} -\frac{1}{d_o} =\frac{1}{f}[/tex]

here,

[tex]d_o[/tex] = Object location

[tex]d_i[/tex] = Image location

[tex]f[/tex] = Focal length

On putting the values in the above expression, we get

⇒ [tex]\frac{1}{48} -\frac{1}{\infty} =\frac{1}{f}[/tex]

             [tex]f=48 \ cm[/tex]  

or,

             [tex]f=0.48 \ m[/tex]

hence,

The refractive power will be:

⇒ [tex]P=\frac{1}{f}[/tex]

       [tex]=\frac{1}{0.48}[/tex]

       [tex]=2.08 \ D[/tex]

Answer:

C

Explanation:

Answer:

P V = n R T      ideal gas equation

V = k T     where k = a constant and equals k = n R / P

V is proportional to T when other factors are constant

Explanation:

KE = (1/2)mv^2 ---> m = 2KE/v^2 = 2(9.890 J)/(10.1 m/s)^2

= 0.194 kg

Note: I think there's something wrong with the energy value given. The mass value for Usain Bolt is too small. That's less than a pound!

Since Taylor has set this fitness goal: I will go to the YMCA and lift weights for 30 minutes every other day for the entire month of January. The option that MOST likely TRUE about this goal is option A:It is a short-term goal.

A short-term goal is a goal that can be achieved within a relatively short period of time, usually less than a year. In this case, the goal is to go to the YMCA and lift weights for 30 minutes every other day for the entire month of January.

In this case, Taylor's goal is to go to the YMCA and lift weights for 30 minutes every other day for the entire month of January. This goal is specific, as it clearly states what Taylor wants to accomplish, and it is measurable.

This goal can be achieved within the month of January and it's a specific, measurable and time-bound goal, which are characteristics of short-term goals.

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See full question below

Taylor has set this fitness goal: I will go to the YMCA and lift weights for 30 minutes every other day for the entire month of January. What is MOST likely TRUE about this goal?

It is a short-term goal.

It is a long-term goal.

It is an unrealistic goal.

It is a mental health goal.

Answer:it’s a short-term goal

Explanation:

because it’s only for the month of January she will be doing this goal.

Answer:

false.

Explanation:

Since temperature and kinetic energy of molecules are proportional, the more we increase the temperature of the solvent, the faster the solute will dissolve.

This increase of kinetic energy allows the solvent molecules to more effective break apart the solvent molecules that are held together by intermolecular forces.