Repeating your experiment _____. A. increases validity B. decreases validity C. has no effect on validity

Answer:

B

Explanation:

The other two choices are exact. B is estimating and giving an indirect observation.

b. scientist traps fish and  

estimates the population of male and female fish based on the ratios of fish he trapped.

The key word is estimate. Estimate means that he gives a rough number. There aren't exactly that number of fish.

A. and C. are both exact numbers because the scientists manually count each one. This means these are direct observations, and therefore not the answer.

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There are no true statements on the list you posted.

Explanation:

Average velocity = change in position over change in time.

v = (x − x₀) / t

Average velocity is defined as the displacement divided by the time of travel.

Average velocity is defined as the displacement (change in position) divided by the time of travel. It can be calculated using the formula:

Average velocity = Displacement / Time

For example, if an object moves 100 meters and takes 10 seconds to do so, the average velocity would be 10 meters per second.

Answer:

J.J. Thomson carried out an experiment in which he find the charge to mass ratio of electron.

Explanation:

J.J. Thomson carried out an experiment in which he used cathode rays which are emitted from cathode gun. Later it was proved that the cathode rays which are emitted from cathode gun were actually a beam of negatively charged particles which are known as electrons.

when these cathode rays passes through an electric field these rays get attracted towards the positively charged plate and get repelled by negatively charged plate of electric field. In this way these rays get deflected from its path and by measuring, how much cathode rays get deflected from its path J. J. Thomson was able to determine mass to charge ratio.

Thomson carried out  the experiment by using different types of cathode which are made from different types of metal and he also filled different gases in the discharge tube but every time he got same charge to mass ratio. After repeating the experiment with different types of cathode and different gases, J.J. Thomson concluded that the cathode ray beam is actually consist of negatively charged particle which is a universal component of matter and which is known as electron. He observed that electron has fixed mass.

Answer:

it must have lived through a long span of time

Answer:Option (1)

Explanation: Index fossil are those fossils that appears for a very short period of time in the geological time scale and has a wide geographical distribution. For example, Ammonites.

Index fossils are a good source for rock age determination and also it helps in the correlation of rocks.

Thus, the correct answer is option (1).

The potential difference across 3 Ohm resistor is 20V.

The resistors are connected in parallel which means all the three resistances have a fully potential difference of 20V.

Answer: Yes

Explanation: The Sun like all other stars will eventually go through nuclear fusion. But for a very long time (about 5 billion years) When it does it is more than likely that it will consume the earth as the sun will expand very larger during the process and become a red giant.

The Sun will 'burn out' over a timeline of billions of years as it exhausts its hydrogen fuel, eventually expanding into a red giant and later leaving behind a cooling white dwarf.

The Sun, which has been shining for about 4.5 billion years, radiates an immense amount of energy due to nuclear fusion occurring in its core. This process involves fusing hydrogen atoms into helium, releasing energy in the form of light and heat. However, the Sun's hydrogen fuel is finite and will eventually be exhausted. In roughly 5 billion years, the Sun will expand into a red giant, engulfing the inner planets. Subsequently, it will shed its outer layers and leave behind a white dwarf. The transition to a red giant will mark the end of the Sun's ability to support life on Earth as we know it. As this white dwarf cools over billions of years, the Sun will indeed 'burn out,' but over a timeline that greatly surpasses human history. Hence, the fate of the Sun is to ultimately cease shining, but this eventuality lies far in our planet's future.

Answer: [tex]a_{apple}=9.082m/s^{2}[/tex], [tex]a_{Earth}=3.027(10)^{-25}m/s^2[/tex]

Explanation:

According to Newton’s law of universal gravitation, which is a classical physical law that describes the gravitational interaction between different bodies with mass:  

[tex]F=G\frac{Mm}{r^2}[/tex] (1)

Where:  

[tex]F[/tex] is the module of the force exerted between the apple and the Earth

[tex]G=6.674x10^{-11}\frac{m^{3}}{kgs^{2}}[/tex] is the universal gravitation constant.  

[tex]M=6(10)^{24}kg[/tex] is the mass of the Earth and [tex]m=200g=0.2kg[/tex] is the mass of the apple

[tex]r=6.64(10)^{6}m[/tex] is the distance between the apple and the Earth (assuming tha apple is near the surface of the Earth)

On the other hand, according Newton's 2nd Law of Motion the force [tex]F[/tex] is directly proportional to the mass [tex]m[/tex] and to the acceleration [tex]a[/tex] of a body.  

So, in the case of the apple:  

[tex]F=m.a_{apple}[/tex] (2)

[tex]a_{apple}=\frac{F}{m}[/tex] (3)

Substituting [tex]F[/tex] (1) in (3):

[tex]a_{apple}=\frac{F}{m}=G\frac{M}{r^2}[/tex] (4)

[tex]a_{apple}=6.674x10^{-11}\frac{m^{3}}{kgs^{2}}\frac{6(10)^{24}kg}{(6.64(10)^{6}m)^2}[/tex] (5)

[tex]a_{apple}=9.082m/s^2[/tex] (6)

Now, in the case of the Earth:  

[tex]F=M.a_{Earth}[/tex] (7)

[tex]a_{Earth}=\frac{F}{M}[/tex] (8)

Substituting [tex]F[/tex] (1) in (8):

[tex]a_{Earth}=\frac{F}{M}=G\frac{m}{r^2}[/tex] (9)

[tex]a_{Earth}=6.674x10^{-11}\frac{m^{3}}{kgs^{2}}\frac{0.2kg}{(6.64(10)^{6}m)^2}[/tex] (10)

[tex]a_{Earth}=3.027(10)^{-25}m/s^2[/tex] (11)

As we can see, the acceleration of the apple towards the Earth is greater than the acceleration of the Earth towards the apple (although the gravitational force between them is the same), because the mass of the Earth is greater than the mass of the apple.

Explanation:

The sources of tax revenue  for federal,state and local government is personal income ,payroll and sales.

Government take some taxes if the income of person is beyond a specified limit.That limit is specified by government itself.

Government  also take some taxes from sales product.

When public or enterprises pay payment online then government take some taxes.

Answer:

Right Hand Rule

Explanation:

When a charged particle travels in a magnetic field, it experiences a force whose magnitude is given by:

[tex]F=qvBsin\theta[/tex]

where

q is the charge of the particle

v is the velocity

B is the magnetic field strength

[tex]\theta[/tex] is the angle between the directions of v and B

The direction of the force can be determined by using the Right Hand Rule, as follows:

- index finger: this should be put in the direction of the velocity

- middle finger: this should be put in the direction of the magnetic field

- thumb: this will give the direction of the force -> however, for a negative charge (as the electron) the direction must be reversed, so it will be opposite.

Answer:

right hand rule

Explanation:

Answer:

B. It is lower due to the Doppler effect.

Explanation:

According to the Doppler effect, observed frequencies are higher than the source frequency if the source is moving towards the observer, and lower if the source is moving away from the observer.

After the ambulance passes, it is moving away from you, so the frequency you hear is lower than the frequency at the ambulance.

Answer:

B. It is lower due to the Doppler effect.

Explanation:

Final answer:

The potential energy of a 0.005 kg coin dropped from a height of 3 m, right before it hits the ground, can be calculated using the formula PE = mgh. The calculated potential energy is 0.147 joules.

Explanation:

To calculate the potential energy of the coin right before it hits the ground, we need to use the formula for gravitational potential energy, which is PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height from which the object falls.

In this scenario:

Mass (m) of the coin = 0.005 kg

Acceleration due to gravity (g) = 9.8 m/s²

Height (h) from which the coin is dropped = 3 m

Substituting these values into the formula, we get:

PE = (0.005 kg) × (9.8 m/s²) × (3 m)

PE = 0.147 J

Therefore, the potential energy of the coin right before it hits the ground is 0.147 joules.

Answer:

75%

Explanation:

I assume the effort is 200 N, not 2000.

The load is 20 cm from the fulcrum, and the crowbar is 1 m long, so the effort is applied 80 cm from the fulcrum.  So the theoretical load that can be raised is:

20 cm × F = 80 cm × 200 N

F = 800 N

But the actual load is 600 N.  So the efficiency is:

e = 600 N / 800 N

e = 0.75

The efficiency of the crowbar is 75%.

Answer:They may cause motion to change

Explanation:They may cause motion; they may also slow, stop, or change the direction of motion of an object that is already moving. Since force cause changes in the speed or direction of an object, we can say that forces cause changes in velocity. Remember that acceleration is a change in velocity.

A force can change the motion of an object that is already moving by altering its velocity or direction.

A force can change the motion of an object that is already moving by altering its velocity or direction.

If a force is applied in the same direction as the object's motion, it can increase its speed. For example, pushing a car that is already moving will make it go faster.

If the force is applied in the opposite direction to the object's motion, it can decrease its speed or even bring it to a stop. For example, dragging your feet on the ground while riding a bicycle will slow you down.

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Explanation:

There are three points in time we need to consider.  At point 0, the mango begins to fall from the tree.  At point 1, the mango reaches the top of the window.  At point 2, the mango reaches the bottom of the window.

We are given the following information:

y₁ = 3 m

y₂ = 3 m − 2.4 m = 0.6 m

t₂ − t₁ = 0.4 s

a = -9.8 m/s²

t₀ = 0 s

v₀ = 0 m/s

We need to find y₀.

Use a constant acceleration equation:

y = y₀ + v₀ t + ½ at²

Evaluated at point 1:

3 = y₀ + (0) t₁ + ½ (-9.8) t₁²

3 = y₀ − 4.9 t₁²

Evaluated at point 2:

0.6 = y₀ + (0) t₂ + ½ (-9.8) t₂²

0.6 = y₀ − 4.9 t₂²

Solve for y₀ in the first equation and substitute into the second:

y₀ = 3 + 4.9 t₁²

0.6 = (3 + 4.9 t₁²) − 4.9 t₂²

0 = 2.4 + 4.9 (t₁² − t₂²)

We know t₂ = t₁ + 0.4:

0 = 2.4 + 4.9 (t₁² − (t₁ + 0.4)²)

0 = 2.4 + 4.9 (t₁² − (t₁² + 0.8 t₁ + 0.16))

0 = 2.4 + 4.9 (t₁² − t₁² − 0.8 t₁ − 0.16)

0 = 2.4 + 4.9 (-0.8 t₁ − 0.16)

0 = 2.4 − 3.92 t₁ − 0.784

0 = 1.616 − 3.92 t₁

t₁ = 0.412

Now we can plug this into the original equation and find y₀:

3 = y₀ − 4.9 t₁²

3 = y₀ − 4.9 (0.412)²

3 = y₀ − 0.83

y₀ = 3.83

Rounded to two significant figures, the height of the tree is 3.8 meters.

Answer:

B. 179.5 N

Explanation:

Weight is mass times acceleration due to gravity:

W = mg

W = (50 kg) (3.59 m/s²)

W = 179.5 N

Answer:

34 m/s

Explanation:

Centripetal acceleration is:

a = v² / r

Given a = 6.55 × 9.8 m/s² = 64.2 m/s², and r = 18 m:

64.2 m/s² = v² / (18 m)

v = 34 m/s

The speed of the centrifuge is 34 m/s.

Answer:

34 m/s

Explanation:

Answer: 226.2 m

Explanation:

If we want to find the new total height [tex]H[/tex] of the building, we have to add to its initial height [tex]h_{B}=225m[/tex] the height of the antenna [tex]h_{A}=1.2m[/tex], as follows:

[tex]H=h_{B}+h_{A}[/tex]

[tex]H=225m+1.2m[/tex]

Then:

[tex]H=226.2m[/tex] This is the new total height of the building.

Answer:

data table and line graph ( first choice)

Answer:

data table and line graph

Explanation:

The data table would consist of the amount of fiber that a student consumes in one column and the grade of the student. So, here the independent variable is amount of fiber that a student consumes and the dependent variable is the grade of the student. The x axis of the graph represents the amount of fiber that a student consumes and the y axis represents the grade of the student.

The line in a graph represents the relationship between the variables of the graph.

Answer:

Centripetal force

Explanation:

Centripetal force acts on an object moving in a circle.  It points towards the center of the circle and has a magnitude equal to m v² / r, where m is the object's mass, v is the object's velocity, and r is the radius of curvature.

Explanation:

the process by which heat or electricity is directly transmitted through the material of a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.

Final answer:

Conduction is the process of transferring heat through direct contact between two objects at different temperatures, as seen when you hold a glass of ice water or cook a steak on a skillet.

Explanation:

Conduction is the process of heat transfer through stationary matter by means of physical contact. Heat essentially moves from a higher temperature region to a lower temperature one within the material. It's the same mechanism at play when an electric burner transfers heat to the bottom of a pan, where the particles in the pan attain energy from the particles of the burner by direct contact.

A common experience with conduction is when you hold a glass of ice water and the heat from your hand is transferred to the glass, subsequently melting the ice.

Conduction is also a key process during cooking when, for example, a steak absorbs heat from a hot iron skillet. In both scenarios, heat is conveyed by the energetic motion and collision of particles from a warmer body (the hand or the skillet) to a colder one (the glass or the steak)

Answer:

2.00 N

Explanation:

The weight is the mass times gravity:

W = mg

The mass is the density times volume:

m = ρV

The volume of a cylinder is:

V = πr²h

Therefore:

W = π r² h ρ g

Given r = 2.00 cm, h = 6.00 cm, ρ = 2.70 g/cm³, and g = 9.8 m/s²:

W = π (2.00 cm)² (6.00 cm) (2.70 g/cm³) (1 kg / 1000 g) (9.8 m/s²)

W = 2.00 N

Answer: contain different amounts of energy

Explanation:

The energy [tex]E[/tex] of a photon is given by:

[tex]E=h\nu[/tex]

Where:

[tex]h=6.626(10)^{-34}\frac{m^{2}kg}{s}[/tex] is the Planck constant

[tex]\nu[/tex] is the frequency of the light which is inversely related to the wavelength.

Now, if we have photons of different light waves, this means we have photons with different frequencies.

As the energy of the photon depends on its frequency:

Photons of different light waves contain different amounts of energy.

Photons of different light waves carry different amounts of energy that are proportional to their frequency.

Photons of different light waves contain different amounts of energy. The energy of a photon is proportional to its frequency. A high-frequency wave carries higher energy photons, while a low-frequency wave carries lower energy photons.

Answer:

200 N

Explanation:

Power = work / time

Work = force × distance

Therefore:

Power = force × distance / time

100 W = F × 10 m / 20 s

F = 200 N

He exerted 200 N.

Answer:

200 N

Explanation:

Answer:

The value 9.8 corresponds to g, the acceleration due to gravity in SI units.

Explanation:

This is the answer on Edmentum. :)

The acceleration due to gravity on earth is also known as the value of g on earth is 9.8 m/s2.

Its SI unit is m / s2. It has both magnitude and direction, therefore, a vector value. Acceleration due to gravity is represented by g. The average g g surface at sea level is 9.8 m / s2.

The gravitational force of gravity weighing 1 kg on Earth is 9.8 N. Another way to put that is the gravitational force on the Earth's surface is 9.8 N / kg.

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Answer:

2 meters

Explanation:

time is directly proportional to temperarure where distance is the constant k

therefore

T = t x 2a

28=7 x 2a

28= 14a

a=2m

Answer:

2440 m

Explanation:

The speed of light in air is approximately 3×10⁸ m/s.

The speed of sound in air at 28°C is approximately:

v = 331.4 m/s + 0.6 m/s/°C (28°C)

v = 348.2 m/s

Let's say the distance between you and the storm is x.

Distance = speed × time

x = 3×10⁸ t₁

x = 348.2 t₂

Since t₂ = t₁ + 7:

x / 348.2  = x / 3×10⁸ + 7

Solving for x:

x (1/348.2 − 1/(3×10⁸)) = 7

x = 2440

The storm is approximately 2440 meters away (round as needed).

Answer:

When people move from one culture to another they carry their background and culture with them, it is responsible for shaping their perception and adjustment to a new culture. Culture shock is a common experience for the people who have moved the new country or region, it includes confusion, shock, and disorientation.  Extreme homesickness, avoiding social situations, physical complaints, and sleep difficulties are other symptoms of Cultural shock. However, there are strategies to deal with it. The strategies are to be open-minded and curious, using the observation skills and asking questions. By being open-minded you can change your values according to other cultures, by using your observation skills you can get a complete picture of what is going on in the new environment and by asking  questions you can easily understand others and can make yourself understood.

Answer

Gravitational force is between two object caused by energy in mass. Here when you are in a mine the radius of the earth in case of calculating gravity is reduced to the length between you and the center.

This means the mass of earth is decreasing even though the distance is decreasing. Relative to the decrease in distance squared the decrease in the mass of the second object(earth) is more. As a result your weight decreases.

Answer:

Explanation: that means as you descend into the earth, all of the mass in all the shells above you gets canceled. If the centre of the earth were not molten iron, but instead hollowed out, you would be weightless inside.

The physics problem is actually a little more general. It applies to inverse square force laws such as the electrical force. So if you put an electron inside a positively or negatively charged sphere, it will also have a net force on it of zero.

Answer:

9.2 N

Explanation:

F = ma

F = m Δv / Δt

F = (0.150 kg) (4.4 m/s − 0 m/s) / 0.072 s

F = 9.2 N

Answer:

9.2Newtons

Explanation:

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