Which of the following would best model the Doppler effect?
A. A toy boat moves through a small pool. The water waves around the boat appear to bunch together in front of the boat and spread further
apart behind the boat.
B. A strobe light flickers on and off in a room, causing people to appear to move more slowly.
C. A pencil is held loosely at one end and is moved up and down. This motion creates the illusion that the pencil is made of rubber.
D. A person on a moving train observes that a book is at rest, but a person observing the train from a stationary platform observes that the book
is in motion.

Answer:

In a positive ion, the number of protons is larger than the number of electrons.

In a negative ion, the number of protons is smaller than the number of electrons.

Explanation:

Each proton carries a positive charge of one unit.

Each elec in tron carries a negative charge of one unit.

In an atom, there are as many protons as electrons. Hence, they are neutral.

However, in a positive ion, there are less negative charge than positive charge. Hence the net charge is positive. That also means that there are fewer negatively-charged electrons than positively-charged protons.

Similarly, in a negative ion, there are more negative charge than positive charge. Hence the net charge is negative. That also means that there are more negatively-charged electrons than positively-charged protons.

"the fuel in a nuclear power station is Uranium 235"​

Explanation:

Answer:

A reaction time is something that measures the amount of time for you to respond to a stimulus. For an example the average human reaction time for a visual stimulus is 0.25 seconds, 0.17 seconds for a audio stimulus and 0.15 seconds for a touch stimulus.

Explanation:

Stimulus - A thing or event that evokes a specific functional reaction in an organ or tissue

Final answer:

The mechanical advantage of the machine is 4, indicating it multiplies the input force by a factor of four.

Explanation:

The student is asking about the concept of mechanical advantage (MA), which is a measure of the force amplification achieved by using a tool, mechanical device, or machine system. The mechanical advantage is calculated as the ratio of the output force to the input force. In this case, a machine lifts a load with an output force of 160N when an input force of 40N is applied. Thus, the mechanical advantage of the machine is calculated by dividing the output force by the input force.

MA = Output Force / Input Force = 160N / 40N = 4.

So, the mechanical advantage of the machine is 4, which means the machine multiplies the input force by four times.

Answer:

Protostars

Explanation:

Most stars originally form from protostars.

Answer: true

Explanation:

The answer is true! Hope this helps!! :)

Answer:

Friction force

Explanation:

Friction force is a force that opposes a motion from moving but friction may seem a bad thing but it is very useful for writting and for other things. please give me a like and thank me.

The force that opposes motion between two surfaces is known as friction. It depends on the types of materials and surfaces in contact. There are four types of friction: Static, Sliding, Rolling, and Fluid, and each one has practical applications in our daily lives.

The force that opposes motion between two surfaces is known as friction in physics. Friction is everywhere in our daily lives. It's the force that allows us to walk, ride a bike, or even hold objects in our hands. The amount of friction between two surfaces is dependent on the type of materials in contact and how rough the surfaces are. For example, ice has less friction than gravel.

There are four types of friction: Static, Sliding, Rolling, and Fluid. The friction that opposes motion between two stationary objects (when you try to slide a heavy box, for instance) is known as static friction. When the objects are set in motion, the friction is known as sliding friction. A moving object over the surface like a wheel over the road experiences rolling friction. Fluid friction refers to the resistance between layers within a viscous fluid or when the fluid is moving over a surface. Each type of friction has important practical applications and implications in our day-to-day life.

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Answer:

GRAVITY

Explanation:

Newtons third law, "Gravity" attracts all objects to each other.

Answer:the child is moving at a constant velocity

The velocity of the object is zero (the object is at rest)

Explanation:

A position vs time graph represents the motion of an object; in particular:

For a position-time graph, the slope of the graph is given by

[tex]m=\frac{\Delta x}{\Delta t}[/tex]

where

[tex]\Delta x[/tex] is the change in position

[tex]\Delta t[/tex] is the change in time

However, we see that this is equivalent to the definition of velocity:

[tex]v=\frac{\Delta x}{\Delta t}[/tex]

Therefore, the slope of  a position-time graph is equivalent to the velocity of the object.

And so, a horizontal segment on a position vs time graph means that the object has zero velocity (because the slope is zero).

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Answer:

simplifying the circuit into groups of series and parallel circuits.

Explanation:

Final answer:

The question relates to how white light spreads out or reflects on a white paper and a mirror, governed by the law of reflection in Physics. Diffused light allows a sheet of paper to be visible from multiple angles, while a mirror reflects light at specific angles based on its smooth surface.

Explanation:

The question pertains to the law of reflection in Physics, looking specifically at how light behaves when shining on different surfaces. When a beam of white light shines onto a sheet of white paper, the light is scattered, or diffused, due to the roughness of the paper's surface. This scattering allows the paper to be seen from various angles. In contrast, when the identical beam shines onto a mirror, the light is reflected because of the mirror's smooth surface.

The reflection adheres to the law of reflection, which states that the angle of reflection equals the angle of incidence (θr = θi). White light on yellow paper and yellow light on white paper will result in color changes due to the colors being absorbed or reflected, whereas red and green lights on white paper may combine to produce a different color perception depending on the superposition of the lights.

Answer: The Force exerted on the student by crate will be 100 N.

Explanation: As per the given Question student is trying to push the crate in right direction with the force of 100N.

And we know that, Newton's third law states that every action has equal and opposite reaction.

So from the Newton's 3rd law of motion it is very clear the student must be experiencing the same amount of force which he is applying.

Answer:

To find the total resistance of the circuit:

They are 2 ways to get that ( you can use both methods for 1 exercise)

1- If resistances are series, just add together .

Rt = R1 + R2

2 If are parallel, do the same thing but the inverse of each resistance .

Rt =1/R1 + 1/R2

Final answer:

The total resistance in a circuit with series and parallel components can be calculated by summing the resistances in series and using the reciprocal rule for resistors in parallel, before combining the two results.

Explanation:

To calculate the total resistance in a circuit, one must know the configuration of the resistors, whether they are in series, parallel, or a combination of both. The student's question suggests they are dealing with a combination of series and parallel circuits, requiring different approaches for each section.

For resistors in series, the total resistance, Rtot, is the sum of all individual resistances. So, if we have resistors R1, R2, and R3 in series, the Rtot would simply be R1 + R2 + R3.

In a parallel configuration, the total resistance, Rp, is found using the formula 1/Rp = 1/R2 + 1/R3. After calculating Rp, if this parallel combination is in series with another resistor R1, then the overall total resistance is Rtot = R1 + Rp. To get the value of Rp, one would calculate the reciprocal of the sum of the reciprocals of the individual resistances in parallel, and then take the reciprocal of that result.

By following these rules, and using the correct units and values given for the resistors, students can accurately determine the total resistance of various circuit configurations.

Answer: 3g/cm3

Explanation:

Mass = 8g

Volume = 2.8325 cm^3.

Density = Mass / volume

Density = 8/2.8325 = 3g/cm3

Answer:

Explanation:

Hydrogen is the first element on the periodic table. That tells you there is 1 electron.

Angle of refraction: [tex]34.6^{\circ}[/tex]

Explanation:

Refraction is a phenomenon that occurs when light crosses the interface between two mediums.

When this occurs, the ray of light bends, according to Snell's law:

[tex]n_1 sin \theta_1 = n_2 sin \theta_2[/tex]

where

[tex]n_1,n_2[/tex] are the index of refraction of the two mediums, respectively

[tex]\theta_1[/tex] is the angle of incidence (the angle between the incident ray and the normal to the surface)

[tex]\theta_2[/tex] is the angle of refraction (the angle between the refracted ray and the normal to the surface)

In this problem, we have:

[tex]n_1 = 1.513[/tex] (index of refraction of glass for red light)

[tex]n_2 = 1.331[/tex] (index of refraction of water for red light)

[tex]\theta_1=30^{\circ}[/tex] (angle of incidence)

Therefore, the angle of refraction is:

[tex]\theta_2 = sin^{-1}(\frac{n_1}{n_2}sin \theta_1)=sin^{-1}(\frac{1.513}{1.331}sin 30^{\circ})=34.6^{\circ}[/tex]

The angle of the refracted beam in the water is approximately 22.04 degrees.

 To find the angle of the refracted beam in the water, we use Snell's Law, which relates the angle of incidence, the angle of refraction, and the indices of refraction of the two media. Snell's Law is given by:

[tex]\[ n_1 \sin(\theta_1) = n_2 \sin(\theta_2) \][/tex]

where:

[tex]- \( n_1 \) i[/tex]s the index of refraction of the first medium (air in this case),

[tex]- \( \theta_1 \)[/tex] is the angle of incidence in the first medium,

[tex]- \( n_2 \[/tex]) is the index of refraction of the second medium (water in this case),

[tex]- \( \theta_2 \)[/tex]is the angle of refraction in the second medium.

Given that the angle of incidence [tex]\( \theta_1 \)[/tex] is 30 degrees, and assuming the index of refraction for air [tex]\( n_1 \)[/tex]is approximately 1 (since it is very close to 1), and the index of refraction for water \( n_2 \) is about 1.33, we can rearrange Snell's Law to solve for[tex]\( \theta_2 \):[/tex]

[tex]\[ \sin(\theta_2) = \frac{n_1}{n_2} \sin(\theta_1[/tex]

[tex]\[ \sin(\theta_2) = \frac{1}{2.66} \][/tex]

[tex]\[ \sin(\theta_2) \approx 0.3758 \][/tex]

Now, we take the inverse sine (arcsine) to find the angle [tex]\( \theta_2 \):[/tex]

[tex]\[ \theta_2 = \arcsin(0.3758) \][/tex]

[tex]\[ \theta_2 \approx 22.04^\circ \][/tex]

Therefore, the angle of the refracted beam in the water is approximately 22.04 degrees."

The average speed of the car that travels 300 km in 6 hours is 5 km/hours.

HOW TO CALCULATE AVERAGE SPEED:

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80 joule is momentarily stored in each spring

Solution:

Given that,

The coil springs on a car's suspension have a value of k = 64000 N/m

When the  car strikes a bump the springs briefly compress by 5.0 cm (.05 m)

By compressing the spring, we apply a force over a distance

As a result we have done work on the spring

Doing work means that we have transferred energy to spring in form of elastic potential

Therefore,

k = 64000 N/m

x = 0.05m

The elastic potential energy is given as:

[tex]PE = \frac{1}{2}kx^2[/tex]

Where, "k" is the spring constant and "x" is the displacement

[tex]PE = \frac{1}{2} \times 64000 \times 0.05^2\\\\PE = 32000 \times 0.0025\\\\PE = 80[/tex]

Thus 80 joule is momentarily stored in each spring

The energy momentarily stored in each spring is[tex]\(\frac{1}{2} \times 64000 \times (0.05)^2 = 80\) joules.[/tex]

To find the energy stored in a spring when it is compressed, one can use the formula for elastic potential energy, which is given by:

[tex]\[ U = \frac{1}{2} k x^2 \][/tex]

where U is the elastic potential energy, k is the spring constant, and x is the compression or extension of the spring from its equilibrium position.

Given that the spring constant k is 64000 N/m and the compression x is 5.0 cm (which is 0.05 m when converted to meters), we can substitute these values into the formula:

[tex]\[ U = \frac{1}{2} \times 64000 \times (0.05)^2 \][/tex]

[tex]\[ U = \frac{1}{2} \times 64000 \times 0.0025 \][/tex]

[tex]\[ U = 32000 \times 0.0025 \][/tex]

[tex]\[ U = 80 \][/tex]

Therefore, the energy momentarily stored in each spring is 80 joules.

Answer:

c. Alkaline earth metals

Explanation:

Answer:

The law of conservation of energy applies to eating your favorite food in that the energy contained in the food is being converted to energy usable for the body system after the final digestion(Glucose or simple sugar, amino acid, etc)

Examples of transformation of energy include

(1) Transformation from Chemical energy in battery to light energy in bulb

(2) Transformation of Electrical energy to thermal/Heat energy in electric stove.

Explanation:

The law of conservation of energy states that energy can neither be created or distroy. It can only by converted from one form to another.

Final answer:

The Law of Conservation of Energy states that energy cannot be created or destroyed, but can be transformed. When eating your favorite meal, the chemical energy in the food is transformed into mechanical energy (chewing) and thermal energy (digestion).

Explanation:

The Law of Conservation of Energy states that energy cannot be created or destroyed, but it can be transformed from one form to another. This applies to eating your favorite meal because the food you eat contains chemical energy, which is then converted into other forms of energy as your body digests and metabolizes the food. Two examples of energy transformations in the process of eating your favorite meal are:

1. Chemical to Mechanical Energy: When you chew your food, the muscles in your jaw contract and expand, converting the chemical energy in the food into mechanical energy.

2. Chemical to Thermal Energy: As your body breaks down the food, chemical reactions take place, releasing heat energy in the form of thermal energy.

Answer:

(C) 16

Explanation:

Given:

The amplitude of first wave (s₁) = 20 mm

The amplitude of second wave (s₂) = 5 mm

Intensity of first wave = Iₓ

Intensity of second wave = [tex]I_y[/tex]

The intensity associated with a wave depends on the amplitude of the wave.

The intensity (I) is directly proportional to the square of the amplitude (s) of the wave and is expressed as:

[tex]I=ks^2\\Where\ k\to constant\ of\ proportionality[/tex]

Now, the intensities of the two waves are given as:

[tex]I_x=ks_1^2=k(20)^2\\\\I_y=ks_2^2=k(5)^2[/tex]

Dividing both the intensities, we get:

[tex]\frac{I_x}{I_y}=\frac{k(20)^2}{k(5)^2}\\\\\frac{I_x}{I_y}=\frac{400}{25}\\\\\frac{I_x}{I_y}=16[/tex]

Therefore, the option (C) is correct.

The intensity of a wave is directly proportional to the square of its amplitude. The ratio of Ix to Iy is 16. Therefore, the correct answer is C. 16.

The intensity (I) of a wave is related to its amplitude (A) by the following equation:

I = (1/2) * ρ * v * ω^2 * A^2

Where:

I is the intensity.

ρ is the density of the medium through which the wave is traveling.

v is the velocity of the wave in the medium.

ω is the angular frequency (equal to 2π times the frequency of the wave).

A is the amplitude of the wave.

Since both waves have the same frequency and are traveling through the same medium, ρ and v will be the same for both waves. Therefore, we can simplify the intensity ratio (Ix/Iy) using the amplitude ratio (Ax/Ay) as follows:

Ix/Iy = (1/2) * (ρ * v * ω^2 * Ax^2) / (1/2) * (ρ * v * ω^2 * Ay^2)

The ρ, v, and ω^2 factors cancel out:

Ix/Iy = (Ax^2) / (Ay^2)

Now, we can plug in the values given:

Ix/Iy = (20mm)^2 / (5mm)^2

Ix/Iy = (400mm^2) / (25mm^2)

Ix/Iy = 16

So, Ix/Iy = 16.

Therefore, the correct answer is C. 16.

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Yo sup??

To solve this question we must know that

P=VI

V=120 V

I=2 A

Therefore by using the above formula we get

P=120*2

=240 J

Hope this helps.

Answer: 240watt

Explanation:

V = 120 V

I = 2A

P = IV = 2 x 120

P = 240watt

The correct answer is B) intensity, which denotes the amount of sound wave energy transported per unit time through a unit area.

The amount of energy which is transported past a given area of the medium per unit of time is known as the intensity of the sound wave. Therefore, the correct answer to the question is B) intensity. Intensity is reported in terms of power per unit area (Watts per square meter, W/m2). It is a critical concept in acoustics that describes how sound waves carry energy through a medium, be it a fluid such as air or a solid.

In the process of sound propagation, a vibrating object such as a guitar string, transfers energy to the surrounding medium creating regions of compressions and rarefactions. These regions of varying pressure travel as longitudinal waves, which means they move along the same axis as the direction of the wave. The sound waves carry energy and this energy transfer per unit time across a unit area is what is quantified by the intensity.

Answer: Gravitational force

Explanation:

A non contact force can be described as a force applied to an object by another body that is not in direct contact with it.

For example, an object thrown upwards will return back due to the force of gravity acting on it. So, it means Gravitational force is acting on the body without necessarily being in contact with that body.

Answer:

C

Explanation:

i dont know im just guessing im way too young for this stuff

the time over which a periodic wave repeats describes as a time period.

A wave with a recurrent pattern that controls its wavelength and frequency is called a periodic wave. The time it takes for a waveform to complete one cycle is referred to as a period, and the frequency is the number of cycles per second of time. It has amplitude, period, and frequency characteristics.

Frequency:

Frequency is the number of occurrences of a repeating event per unit of time.

Wavelength:

A waveform signal that is carried in space or down a wire has a wavelength, which is the separation between two identical places (adjacent crests) in consecutive cycles.

Amplitude (A):

The maximum displacement of a wave on either side of its mean position is called Amplitude.

Time Period (T):

The time taken to complete one vibration is called the Time period.

therefore, period describes the time over which a periodic wave repeats.

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Answer:

6 bub

Explanation:

Lifting a heavy box and placing it on a table increases its potential energy due to the work done against gravity. The box remains stationary with this added potential energy. If the box were to fall, this potential energy would be converted into kinetic energy as it accelerates towards the ground.

When you lift an object such as a heavy box and place it on a table, if the box remains stationary, it means that you have changed its energy state. Specifically, you have increased its potential energy. Potential energy is the energy stored in an object as a result of its position or height. For example, in Physics, lifting a 20 kg box of books through a vertical distance of 2m would involve an energy expenditure of approximately 400 J, signifying that the box gained 400 J of potential energy. This energy transfer occurs because of the work done against gravity: applying a force to lift the object off the ground increases its potential energy. Once the object is released, if it falls, the stored potential energy is converted into kinetic energy as it accelerates towards the ground due to the force of gravity.

It is important to note that while lifting the object, if it is done slowly so that the box's speed does not change significantly, the kinetic energy of the object remains constant (nearly zero if lifted slowly enough), although its potential energy increases. This concept is exemplified when an object is lifted using a device powered by chemical energy, such as a gasoline engine; the chemical energy is converted into gravitational energy, which is then stored in the object as potential energy. When it comes to work and energy, the work done on an object adds to its total energy. If that work is done to lift an object against the force of gravity, it is stored as potential energy.

The force exerted by the filled grocery bag when it is lifted with an acceleration of 5.0 m/s² would be 294 N. As this is higher than the maximum force the bag can withstand (250 N), the bag would rip, and the groceries would not stay within it.

The maximum force that a grocery bag can withstand without ripping is 250 N. Suppose that the bag is filled with 20 kg of groceries and lifted with an acceleration of 5.0 m/s²; we need to verify if the groceries stay in the bag. The force exerted by the bag, according to Newton's second law (F=ma), will be the mass of the groceries (m) times the gravitational acceleration (g) plus the additional acceleration due to lifting (a). Here, g=9.8 m/s², and the bag is lifted with a=5 m/s².

The force exerted by the filled grocery bag will be F=(m*(g+a))= 20 kg*(9.8 m/s²+5.0 m/s²)= 294 N.

Since 294 N is greater than the maximum force the bag can withstand (250 N), the bag will rip, and the groceries will not stay in the bag if the bag is lifted with an acceleration of 5.0 m/s².

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Answer:

It needs attractive force from the strong nuclear interaction to counter the electrostatic repulsion between the protons.

Explanation:

It has to counter

Final answer:

Other elements apart from hydrogen need at least one neutron in their nuclei to stabilize the electrostatic repulsion between protons. Neutrons add to the atomic mass and contribute to the stability of atoms. The varying number of neutrons leads to different isotopes of an element which is an essential factor in the structure and behavior of elements.

Explanation:

Neutrons play a key role in the stability of an atom. While hydrogen, with an atomic number of 1, can exist without neutrons in its nucleus, other elements require neutrons to offset the electrostatic repulsion between protons, which are all positively charged. The presence of neutrons in the nucleus contributes to the atomic mass and helps to maintain the stability of atoms as it keeps the protons from repelling each other and breaking the nucleus apart.

Isotopes are versions of the same element with a different number of neutrons, leading to variations in their atomic mass. For example, helium has an atomic number of 2 and an atomic mass of 4 because it has two neutrons in addition to two protons. As we move across the periodic table, the ratio of neutrons to protons in the nucleus generally increases, aiding in the stability of heavier elements.

The atomic mass of an element is not simply its atomic number (the number of protons) but the combination of the number of protons and neutrons. Protons and neutrons have nearly identical masses, and each contributes significantly to the mass of an atom. This concept is integral when considering the structure and behavior of elements and in understanding the composition of the human body, which is largely made up of elements like oxygen, carbon, and hydrogen.

Answer:

Velocity = 4.33[m/s]

Explanation:

The total energy or mechanical energy is the sum of the potential energy plus the kinetic energy, as it is known the velocity and the height, we can determine the total energy.

[tex]E_{M}=E_{p} + E_{k} \\E_{p} = potential energy [J]\\E_{k} = kinetic energy [J]\\where:\\E_{p} =m*g*h\\E_{p} = 4*9.81*0.5=19.62[J]\\E_{k}=\frac{1}{2} *m*v^{2} \\E_{k}=\frac{1}{2} *4*(3)^{2} \\E_{k}=18[J]\\Therefore\\E_{M} =18+19.62\\E_{M}=37.62[J][/tex]

All this energy will become kinetic energy and we can find the velocity.

[tex]37.62=\frac{1}{2} *m*v^{2} \\v=\sqrt{\frac{37.62*2}{4} } \\v=4.33[m/s][/tex]