What are stars made up of at the beginning?

Answer: C- The planets appeared to move backward in the sky occasionally.

Explanation:

wavelength =200cm=2m

frequency is reciprocal of wavelength

f=1/2

f=0.5Hz or 1/s

The frequency of the wave with a Wavelength of 200 cm should be considered as the f=0.5Hz or 1/s.

Since the wavelength is 200 cm or 2m

Also we know that

frequency is reciprocal of wavelength

So,

f=1/2

f=0.5Hz

Hence, The frequency of the wave with a Wavelength of 200 cm should be considered as the f=0.5Hz or 1/s.

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This question is incomplete, the complete question is;

A high-resistance material is used as an insulator between the conductors of a length of coaxial cable. The resistance material, which forms a hollow tube, has an inner radius a and an outer radius b, and the insulator provides a resistance R between the conductors. If a second insulator, made of the same material and having the same length, is made with double both the inner radius and the outer radius of the first, what resistance would it provide between the conductors

a) (In2)R

b) 4R

c) R/(In2)

d) 2R

e) R

Answer: Option e) R is the correct answer.

Explanation:

Given that;

Inner radius = a

Outer radius = b

Conical Cylinder

∫dR = ∫(edr/2πrL)

R = e/2πL In e |ᵇₐ

R = e/2πL In(b/a) ------------- let this be equation 1

Taking a look at the second cone

a' = 2a

b' = 2a

R' = e/2πL In(2b/2a)

{L = L'}

R' = e/2πL In(b/a) -------let this be equation 2

now lets compare the two equation

R = e/2πL In(b/a)

R' = e/2πL In(b/a)

so R' = R

Therefore Option e) R is the correct answer.

Answer:

miami dolphins.

Explanation:

......

Answer:

miami :(

Explanation:

Answer:

protons are in the nucleus .

Explanation:

there are 6 protons

Answer:

electrical energy

Explanation:

sorry I'm really tired but trust me on this one

Answer:

electrical to thermal and light

Explanation:

The FitnessGram Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. A single lap should be completed each time you hear this sound. Remember to run in a straight line, and run as long as possible.

Answer:

Frying an Egg

Explanation:

When chemical bonds are broken or formed, new particles are created. Therefore, frying an egg is a chemical change because it results in the formation of new particles.

Frying an egg is an example of chemical change. Therefore, option (A) is correct.

A chemical change can be described as a change in which a chemical substance is converted into one or more new types of substances. Chemical changes occur through chemical reactions that result in substances with different properties.

Chemical changes are irreversible in nature and are also called permanent changes in which an entirely new substance is formed. We have three kinds of chemical change organic, biochemical and inorganic.

While frying an egg, the egg changes from a fluid to a strong one. The egg changes from a fluid protein into a strong mass.  Actually, the strands of protein extend, permitting the protein to denature by breaking the chemical bonds and formation of a new product.

Therefore, Frying an egg is a chemical change while boiling water, melting butter, and chopping onions are physical changes.

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Answer:

3A. This phenomenon can be seen in the discrete emission of the molecules.

3B. The emotion of the atoms is observed, from states high in energy to a state of minimum energy that is stable indefinitely.

3C. When an electron beam passes through an inhomogeneous magnetic field, it is divided into only two beams

3D. This is due to the stimulated emission

3E. The penetration of a potential barrier is observed in the radioactive emission of heavy atoms, where an alpha particle (Helium nucleus)

Explanation:

This problem asks for some experimental explanations of various quantum phenomena.

3A. This phenomenon can be seen in the discrete emission of the molecules.

In the classical explanation all states or energies are allowed, therefore when emitting energy (photons) there should be a continuum, this is not observed

In the correct quantum explanation only some states are allowed, therefore the emission must be discrete, which is observed in the emission or absorption of molecules and atoms

3B. The emotion of the atoms is observed, from states high in energy to a state of minimum energy that is stable indefinitely.

The incorrect classical explanation that if the minimum energy was zero the electrons cannot rotate around the nuclei and the atom collapses, this does not happen

3C. When an electron beam passes through an inhomogeneous magnetic field, it is divided into only two beams, which is evidence of the existence of two discrete states that we call spin, remember that a free electron beam has zero angular momentum.

3D. This is due to the stimulated emission that occurs when a photon passes through the emission zone, causing the atoms to have transitions and these emitted photons have the same initial photon location, the laser beam all photons are in phase and therefore it is coherent .

This is widely used for holographic and interference work

3E. The penetration of a potential barrier is observed in the radioactive emission of heavy atoms, where an alpha particle (Helium nucleus) leaves the atomic nucleus penetrating the barrier since its energy is lower than the nuclear barrier potential.

Answer:

Explanation:

Please provide some experimental demonstration or explanation of natural observations or characteristics of application which confirm(s) / display(s) the. Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature. Quantum mechanics arose gradually from theories to explain observations. By M Arndt · 2009 · Cited by 239 — Wave-particle duality of light: A paradigmatic example for this fact is the dual nature of light that manifests itself in Young's famous double-slit diffraction.

Answer:

a) ll and Ill only

Explanation:

Let the mass of the wrench = m

and the mass of the astronaut = M

Initially, the velocity of the astronaut and wrench are zero.

The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.

Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.

In space, there is no external force acting, the momentum must be conserved.

So, m(0)+M(0)=m(v)+M(V)

So, 0=mv+MV

[tex]\Rightarrow mv=-MV[/tex] ...(i)

Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.

Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.

According to Newton's second law, the rate of change of momentum = applied force.

Let it take [tex]\Delta t[/tex] seconds to change the momentum.

So, for the wrench

[tex]m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)[/tex]

Here, [tex]F_w\Delta t[/tex] is the impulse applied to the wrench.

Similarly, for the astronaut

[tex]M(-V-0)/\Delta t= F_a[/tex] [negative sign (-V) for opposite direction]

[tex]\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t[/tex]

Here, [tex]F_a\Delta t[/tex] is the impulse applied to the astronaut.

So, the impulse on the astronaut.

By using equations (i) and (ii)

[tex]F_a\Delta t=F_w\Delta t[/tex]

Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.

Hence, option (a) is correct.

Answer:10 m/s

Explanation:

A 100 kg gymnast comes to a stop after tumbling. Her feet do 5,000 J of work to stop her. The girl's velocity when she began to stop is 10 m/sec.

When an item is moving, its velocity is the rate at which its direction is changing as seen from a certain point of view and as measured by a specific unit of time. Velocity is vector quantity.

Uniform motion an object is said to have uniform motion when object cover equal distance in equal interval of time within exact fixed direction. For a body in uniform motion, the magnitude of its velocity remains constant over time. Here in the question velocity is changing by using work energy theorem we have,

work done = change in kinetic energy

5000 = (.5).m.v² , where v is velocity.

5000 = (.5).100.v²

v = 10 m/sec

A 100 kg gymnast comes to a stop after tumbling. Her feet do 5,000 J of work to stop her. The girl's velocity when she began to stop is 10 m/sec.

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Answer and Explanation:

--> MRI (Magnetic Resonance Imaging) is an imaging technique that involves the use of radio waves and magnetic field to generate high detailed images of the human body. It's clinical applications includes:

• Bone and joint MRI:  these are done to check for bone and joint problems such as bone marrow disorders, arthritis, or bone tumours.

• A Spine MRI: This is used to investigate the spinal disc and innervations for disorders such as spinal tumours.

• Chest MRI: This is used to detect abnormalities of the heart, heart valves and coronary arteries.

--> X-RAY: These are electromagnetic waves of short wavelength with high penetrating power. They are produced when fast moving electrons strike a mass of heavy atoms such as those of metals. It's applications includes:

• They are used to detect hidden cracks in materials.

• They are used to show broken bones in human body.

• They are used in the study of internal structures of crystals.

• In agriculture, x-rays are used in killing germs.

--> ULTRASOUND: This makes use of high frequency sounds to detect abnormalities in the human body. An ultrasound machine transmits sound waves into the body which are reflected at the surfaces between the tissues of different density. It can also be used in different disciplines such as imaging, cleaning, mixing, navigation and communication   It's applications includes:

•. Detection of Cracks: when applied on metallic surface under investigation, high frequency sound wave reflects back which and be predicted and recorded.

--> INFRARED RADIATION: This is a type of electromagnetic radiation with wavelength longer than visible light. It is visible to the human eye and most heated surfaces transmits infrared radiation. It's applications includes:

• it is used for the purpose of sensing and detection. For example the night vision goggles and infrared cameras. Remote control makes use of infrared light waves to change channels in the television.

distance ; time

Explanation:

wavelength is in metres [m]

period is in seconds [s]

Answer:

PLEASE MARK AS BRAINLIEST!!

Explanation:

A getting passenger getting down from a moving bus, falls in the direction of the motion of the bus. This is because his feet come to rest on touching the ground and the remaining body continues to move due to inertia of motion.

Answer:

When the person steps on the ground, his feet do not move but his upper body moves in the direction of the bus due to inertia of its motion. Since his upper body moves in the forward direction and his lower body does not move, the person falls in the forward direction.

Answer:

The water cycle shows the continuous movement of water within the Earth and atmosphere. ... Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere (transportation).

Explanation:

It's the water cycle.

Answer:

When an object moves with a constant speed in a circular path, then its motion is called as Circular motion.

Examples of Uniform Circular Motion :--

The moon moves in uniform circular motion around the earth.

A stoned tied to a thread and rotated in circular motion.

An athlete running on a circular track.

A satellite revolving around Earth.

Answer:

A I think

Explanation:

because what is the most frequency a because it has more frequency I think I'm not that sure

Answer:

The value is  [tex]|v| = 7.39 \ m/s[/tex]

Explanation:

From the question we are told that

    The angular speed is  [tex]w = 2030 \ rpm = \frac{2030 * 2 * \pi }{ 60} = 212.61 \ rad/s[/tex]

    The distance between the minimum and maximum external position is  [tex]d = 6.95 \ cm = 0.0695 \ m[/tex]

Generally the amplitude of the crank shaft is mathematically represented as

         [tex]A = \frac{d}{2}[/tex]      

=>     [tex]A = \frac{0.0695}{2}[/tex]    

=>     [tex]A = 0.03475 \ m[/tex]

Generally the maximum speed of the piston is mathematically represented as

        [tex]|v| = A * w[/tex]  

=>    [tex]|v| = 0.03475 * 212.61[/tex]

=>    [tex]|v| = 7.39 \ m/s[/tex]

Complete question

The diagram for this question is shown on the first uploaded image

Answer:

The largest possible distance is [tex]e = 15.33 \ m[/tex]

Explanation:

From the question we are told that

   The separation between Speaker at  position  A and B  is  AB =  6.60 m

   The frequency of the tune which the speaker are playing is [tex]f = 126 \ Hz[/tex]

    The speed of sound is [tex]v = 343 \ m/s[/tex]

Generally the wavelength of the tune playing is mathematically represented as

           [tex]\lambda = \frac{v}{f}[/tex]

=>        [tex]\lambda = \frac{343}{ 126}[/tex]

=>        [tex]\lambda = 2.72 \ m[/tex]

Let the observer be at position D

Generally the distance A and  is mathematically  evaluated using  Pythagoras theorem as

       [tex]AC = \sqrt{AB ^2 + BC^2}[/tex]

Let BC = e

So  

       [tex]AC = \sqrt{6.60 ^2 + e^2}[/tex]

Generally the path difference between the first and the second speaker from the observer point of view is mathematically represented as

       [tex]P = AC - BC[/tex]

=>     [tex]P = \sqrt{6.60 ^2 + e^2} - e[/tex]

Generally the condition for destructive interference is mathematically represented as

            [tex]P = (2n - 1 )\frac{\lambda}{2}[/tex]

Here n is the order of the fringe which is  one

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = (2 * 1 - 1 )\frac{2.72}{2}[/tex]

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = 1.36[/tex]

=>        [tex]6.60 ^2 + e^2 =( 1.36 +e)^2[/tex]

=>        [tex]6.60 ^2 + e^2 =1.8496 + 2.72e +e^2[/tex]

=>          [tex]e = 15.33 \ m[/tex]

Answer:

First answer to the first question is Two people pulling a rope with the same force in a opposite direction.  The other one would be 2.72N        

Explanation:

Hope this helps you :)

Answer:

I guess the Ans for second one is gravitational force

Answer:

MA = 2.5

Explanation:

Given that,

Effort force applied to a screwdriver to pry the lid off of a can= 40 N

The screwdriver applies 100n of force to the lid = 100 N

We need to find the mechanical advantage of the screwdriver. Mechanical advantage of a machine is given by the ratio of load to the effort.

m = load/effort

= 100/40

= 2.5

Hence, the MA of the screwdriver is 2.5

Answer:

1)    x_{cm} = 5 m ,  2)  I = 168.32 kg m²

Explanation:

1) An important concept of center of mass is

          [tex]x_{cm} = \frac{1}{M} \sum x_{i} m_{i}[/tex]

where M is the total mass of the system

Let's apply this equation to our case, suppose that all masses are equal and are worth 1 kg

         [tex]x_{cm}[/tex] = ⅓ (1 0 + 1 5 + 1 10)

         x_{cm} = 5 m

2) In this para indicates that there is an axis of rotation at the point xo = 3.8 m and they ask to calculate the moment inertia.

Let's use the parallel axes theorem

          I =    I_{cm} + M D

where    I_{cm}  is the moment of inertia with respect to the center of mass, D the distance between the two axes of rotation and M the total mass of the system

Let's look for the moment of inertia of the center of mass

         [tex]I_{cm}[/tex] = 1  0 + 1  5² + 1  10²

         I_{cm} = 125 kg m²

the total moment of inertia is

        I = 125 + 3 3.8²

        I = 168.32 kg m²

The moment of inertia of the 3-mass system about the new axis is 54.32 kgm/s².

We have three masses each of mass = 1kg such that they are in line with mass m at origin, m at 5m and m at 10m

(a) The center of mass:

[tex]X=\frac{m_1x_1+m_2x_2+m_3x_3}{m_1+m_2+m_3} \\ \\ X =\frac{ 1*0+1*5+1*10}{1+1+1}\\ \\ X = 5m[/tex]

Hence the center of mass of the system is at x = 5m.

(b) The moment of inertia about the axis passing through x = 3.8m

from the parallel axis theorem:

[tex]I = I_{cm} + Md^2[/tex]

where, [tex]I_{cm}[/tex] is the moment of inertial along an axis passing through the center of mass of the system, M is the total mass of the system and d is the distance of the given axis from center of mass.

M = 3kg

d = 5 - 3.8 = 1.2m

[tex]I_{cm}=1*5^2+1*0+1*5^2\\\\ I_{cm}=50 kgm/s^2[/tex]

Md² = 3×(1.2)²

Md² = 4.32 kgm/s²

I = 50 + 4.32

I = 54.32 kgm/s² is the moment of inertial about the given axis.  

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Answers: 1) 3 kg m²

                2) 2.88 kg m²

Explanation: Question 1

                      I = m(r)²+ M(r)²

                      I = 1.2 kg × (1 m )² +1.8 kg ×(1 m )²

                    ∴  I =   3 kg m²

                      Question 2

ACCORDING TO THE DIAGRAM DRAWN FOR QUESTION 2

we have to decide where the center of gravity (G) lies and obviously it should lie somewhere near to the greater mass. (which is 1.8 kg). Since we don't know the distance from center of gravity(G) to the mass (1.8 kg) we'll take it as 'x' and solve!!

moments around 'G'

F₁ d ₁ = F₂ d ₂

12 (2-X) = 18 (X)

24 -12 X =18 X

∴  X = 0.8 m

∴ ( 2 - x ) = 1.2 m

∴ Moment of inertia (I) going through the center of mass of two masses,

⇒ I = m (r)² +M (r)²

⇒ I = 1.2 × (1.2)² + 1.8 × (0.8)²

⇒ I = 1.2 × 1.44 + 1.8 × 0.64

⇒ I = 1.728 + 1.152

⇒ ∴ I = 2.88 kg m²

∴ THE QUESTION IS SOLVED !!!

Answer:

m1 ÷ m2 = 1 ÷ 2

Explanation:

The ratio of their masses is as follows:

As it is given that the mass m1 is twice of mass m2

So the equation could be written as

[tex]\frac{1}{2} m1 v1 v1 = 2 \times \frac{1}{2} m2 v2 v2\\\\\frac{m1}{m2} = \frac{2 v2 v2}{v1 v1} ..........(1)[/tex]

Here we used the  conservation of momentum

Prior to the explosion, the object is in rest so the momentum would be zero but after the explosion the total momentum would be  m1v1 + m2v2,  that is also zero.

So,

[tex]m1 v1 + m2 v2 = 0\\\\m1 v1 = - m2 v2\\\\\frac{m1}{m2} = \frac{- v2}{v1}[/tex]

Now squaring to the both sides

m1 m1 ÷ (m2 m2) = v2 v2 ÷ (v1 v1) ........(2 )

Solved both the equations

After solving it, the ratio is

m1 ÷ m2 = 1 ÷ 2

My opinion about friction is that It always acts in the opposite direction as the motion of the object.

Friction refers to the resistance of motion of one object that is moving relative to another object. Fricton has many application but it has also many disadvantages.

So we can conclude that friction is always acts in the opposite direction as the motion of the object.

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Considering the Ohm's law, the correct answer is option B. the current is 0.048 A.

The flow of electricity through an object, such as a wire, is known as current (I). Its unit of measure is amps (A). So the current is a measure of the speed at which the charge passes a given reference point in a specified direction.

The driving force (electrical pressure) behind the flow of a current is known as voltage and is measured in volts (V) (voltage can also be referred to as the potential difference or electromotive force). That is, voltage is a measure of the work required to move a charge from one point to another.

Resistance (R) is the difficulty that a circuit opposes to the flow of a current and it is measured in ohms (Ω).

Ohm's law establishes the relationship between current, voltage, and resistance in an electrical circuit.

This law establishes that the intensity of the current that passes through a circuit is directly proportional to the voltage of the same and inversely proportional to the resistance that it presents.

Mathematically, Ohm's law is expressed as:

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

Where I is the current measured in amps (A), V the voltage measured in volts (V); and R the resistance that is measured in ohms (Ω).

In this case, you know that the voltage between two points in a circuit is 3.6 V and the resistance between the points is 75 Ω.

Replacing in the Ohm's Law:

[tex]I=\frac{3.6 volts}{75 ohm}[/tex]

Solving:

I= 0.048 amps

Finally, the correct answer is option B. the current is 0.048 A.

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Question 4

B. Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.

Question 5

At the maximum height, velocity is 0, so:

v = v₀ - gt

0 = 14.75 - 9.8t

t = 14.75/9.8

t = 1.5 s    (OPTION A)

4). In the given situation, the assertion that could be made regarding Toby would be:

B). Toby is correct because the rock is experiencing a negative acceleration, causing its positive velocity to decrease until the rock reaches a velocity of O m/s before becoming negative.

5). The time that would be taken by the rock to attain its greatest height would be:

1.5 second

4). Tobby correctly states as rock would be undergoing a -ve acceleration which leads its +ve velocity to fall by the time rock attains the velocity of 0 m/s.

Thus, option B is the correct answer.

5). Given that,

Initial velocity([tex]v_{0}[/tex]) = 14.75 m/s

As we know,

Velocity remains 0 m/s at the greatest height,

So,

Velocity(v) [tex]= v_{0} - gt[/tex]

where

[tex]0 = 14.75 - 9.8t[/tex]

⇒ [tex]t = 14.75/9.8[/tex]

 ∵ [tex]t = 1.5 s[/tex]

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Answer:

The  correct option is D

Explanation:

From the question we are told that

  The intensity of the first  electromagnetic wave is  [tex]I = 18 \ W/m^2[/tex]

  The amplitude of the electric field is  [tex]E_{max}_1 =A[/tex]

   The intensity of the second electromagnetic wave is  [tex]I = 36 \ W/m^2[/tex]

Generally the an electromagnetic wave intensity is mathematically represented as

       [tex]I = \frac{1}{2} * \epsilon_o * c * E_{max}^2[/tex]

Looking at this equation we see that

     [tex]I \ \ \alpha \ \ E^2_{max}[/tex]

=>  [tex]\frac{I_1}{I_2} = [ \frac{ E_{max}_1}{ E_{max}_2} ] ^2[/tex]

=>   [tex]E_{max}_2 = \sqrt{\frac{x}{y} } * E_{max}_1[/tex]

=>  [tex]E_{max}_2 = \sqrt{\frac{36}{18} } * E[/tex]        

=>  [tex]E_{max}_2 = \sqrt{2 } E[/tex]