Which statement about electromagnetic waves is true?

A.
Electromagnetic waves require a medium to travel.
B.
Electromagnetic waves don't require a medium to travel.
C.
The particles of the medium through which electromagnetic waves travel vibrate perpendicularly to the direction of the wave.
D.
The particles of the medium through which electromagnetic waves travel vibrate parallel to the direction of the wave.

Answer:

80 Percent

Explanation:

E=energy output/energy input×100

E=8000/10000×100

E=0.8×100

E=80 percent.

Mark brianliest if my answer suit your question

If the machine put, in 8000 J, and the user puts 10,000 J of work then the efficiency of the machine will be equal to 80%.

Work is a physics term used to describe the transfer of energy that takes place when an object changes above a distance because of an external force, at least some of which is given in the vector of the dislocation. The element of the force acting all along the path multiplied by the length of the path can be used to calculate work if the force is constant.

Mathematically, this idea is expressed as W = fd, where W is the effort and f is the force multiplied by d, the distance. Work is completed whenever the force is applied at an angle with about the displacement.

As per the data provided in the question,

Total input energy = 10,000 J

Total output energy = 8,000 J

Then, the efficiency (η) of the machine will be,

η = (output energy/input energy) × 100

η = 8000/10000 × 100

η = 80%.

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Answer:

c

Explanation:

The amount of mass used up in holding a nucleus together the mass defect represent.

Thus, The term "mass defect" refers to the discrepancy between the actual atomic mass and the expected mass obtained by multiplying the mass of the protons and neutrons in the nucleus by a constant factor.

The anticipated mass obtained by combining the masses of the nucleons is less than the actual atomic mass. The binding energy that is produced when a nucleus forms accounts for this extra mass.

The mass defect is a result of some of the mass being converted to energy during the formation of a nucleus. The real mass of an atomic nucleus is therefore less than the mass of the constituent particles.

Thus,  The amount of mass used up in holding a nucleus together the mass defect represent.

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Answer:

x = 4.32 [m]

Explanation:

We must divide this problem into three parts, in the first part we must use Newton's second law which tells us that the force is equal to the product of mass by acceleration.

∑F = m*a

where:

F = force = 700 [N]

m = mass = 2030 [kg]

a = acceleration [m/s²]

Now replacing:

\(F=m*a\\700=2030*a\\a = 0.344[m/s^{2}]\)

Then we can determine the final speed using the principle of conservation of momentum and amount of movement.

\((m_{1}*v_{1})+Imp_{1-2}=(m_{1}*v_{2})\)

where:

m₁ = mass of the car = 2030 [kg]

v₁ = velocity at the initial moment = 0 (the car starts from rest)

Imp₁₋₂ = The impulse or momentum (force by the time)

v₂ = final velocity after the impulse [m/s]

\((2030*0) + (700*5)=(2030*v_{2})\\3500 = 2030*v_{2}\\v_{2}=1.72[m/s]\)

Now using the following equation of kinematics, we can determine the distance traveled.

\(v_{2}^{2} =v_{1}^{2}+2*a*x\)

where:

v₂ = final velocity = 1.72 [m/s]

v₁ = initial velocity = 0

a = acceleration = 0.344 [m/s²]

x = distance [m]

\(1.72^{2}=0^{2} +(2*0.344*x) \\2.97 = 0.688*x\\x = 4.32 [m]\)

Answer:

208 is the surface area!

Explanation:

Hope this helps! ;-)

The magnetic field of the solenoid will be 30.79 T.

Magnetic field strength is a quantitative measure of the strength or weakness of a magnetic field.

Length of solenoid, L = 1.5 cm = 0.015 m

Radius of solenoid, r = 0.65 cm = 0.0065 m

Number of turns, N = 49 turns

Current, I = 1.45 A

Magnetic field, B, can be calculated as B = (N*r*I) /L

B = (49 * 0.0065 * 1.45)/0.015

B =  30.79 T

The magnitude of the magnetic field inside the solenoid is 30.79 T.

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Answer: YES.

Explanation: OK, lets say you have a basket of fruit, it has a large mass, and a large gravity, it takes more force to lift it up. now, if we try to carry it lets say, across the yard, its gonna be pretty heavy! now, when we put it in a wheel barrow, the force goes onto the wheels. it takes less force to move it.

Answer:

At the top of the roller coaster, there is a lot of potential energy. When it comes to the bottom, the roller coaster loses its potential energy and gains kinetic energy as it is going very fast here.

The kinetic energy of a roller coaster as it approaches its lowest point will be maximum and loses its potential energy.

The energy of the body by the virtue of its motion is known as the kinetic energy of the body. It is defined as the product of half of mass and square of the velocity.

According to the law of conservation of energy, the total energy is defined as the sum of kinetic energy and potential energy.

Total energy = kinetic energy+potential energy

Potential energy is due to the position.While the kinetic energy is due to the velocity.

There is a maximum potential energy at the top of the roller coaster. As it nears the bottom, the roller coaster loses potential energy and acquires kinetic energy due to the high speed.

Hence,the energy of the body by the virtue of its motion is known as the kinetic energy of the body

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Answer:

Kinetic energy is 2886.5Joule

Answer:

maximum shear stress = τ(max) = 95.49 × 10⁶N/m²

Explanation:

given

outer diameter at one end(D₁) = 3.0cm

outer diameter at the other end(D₂) = 4.0cm

inner diameter(d₁) = 1.0cm

torque applied(T) = 500Nm

maximum shear stress will occur at lower outer diameter

the formula is τ/r = T/J

τ= T × r/J

where r is radius

T is the torque

J is the polar 2nd M of area

attached is the calculation of the question

A box is pushed across a rough horizontal floor by a force acting parallel to the floor in the direction of motion. A force doing negative work on the box pushed across a rough horizontal floor is friction.

So, the correct answer is C.

As the box is moved by an applied force parallel to the floor, friction opposes the motion, acting in the opposite direction.

This opposition causes the frictional force to do negative work, as it resists the movement and reduces the box's kinetic energy.

Meanwhile, (a) gravity and (d) the normal reaction force act perpendicular to the motion, resulting in no work being done by these forces. (b) The applied force does positive work, contributing to the box's motion. (e) A fictitious force is not applicable in this scenario.

Hence, the answer of the question is C

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Answer:

Horizontal component = 60.05 m/s

vertical component = 22.96 m/s

Explanation:

cosine(angle) = adjacent / hypotenuse or  horizontal / angled velocity

angled velocity * cosine (angle) = horizontal velocity

65 m/s * cosine(22.5) = 60.05 m/s

sine(angle) = adjacent/ hypotenuse or vertical/ angled velocity

angled velocity * sine (angle) = vertical velocity

65m/s sine(22.5) = 22.96 m/s

By using the concept of work and energy, the below are the answers

1. 100J

2. 100J

3. 0

4. Total energy = K.E + P.E

5. 1.02 kg

6. 14 m/s

Given that 100 J of work was done to lift a 10-N rock and set it at Position A near the edge of a cliff.

1. If the 100 Joules of work lifted the rock to the top of the cliff, how much potential energy did the rock gain?

Work is the product of force and the distance.

The potential energy gained by the rock will be equal to work done in lifting  up the rock which is 100 J

2. At point C, the rock's potential energy will be equal to the work done.

That is, at point C, P.E = 100J

3. The rock's kinetic energy at point A is Zero.

That is, at point A, K.E = 0

4. At point B, some of the rock's potential energy will be changed to Kinetic energy. Yes. Because the Total energy = K.E + P.E

5. What is the mass of the rock?

Weight W = mg

where g = 9.8m/s^2

W = 10N

Substitute both into the formula

10 = 9.8m

make m the subject of the formula

m = 10/9.8

m = 1.02 kg

6. What is the rock's velocity just before it hits the ground

Work done = Energy

That is, Work done = maximum P.E = maximum K.E

100 = 1/2m\(v^{2}\)

Substitute mass into the formula

200 = 1.02\(V^{2}\)

V = \(\sqrt{196}\)

V = 14 m/s

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Answer:

3)No, it's speed is constant.

Answer:

D

Explanation:

Trees are obviously effected from deforestation.

Pollution effects the things trees need to grow (water, air).

Reduction removes parts of the tree, some parts being needed.

Answer: D

Explanation:Trees are obviously effected from deforestation.

Pollution effects the things trees need to grow (water, air).

Reduction removes parts of the tree, some parts being needed.

It is estimated that there is b. 20 to 30 times as much more water stored underground than in all the surface streams and lakes.

This significant amount of water is found in aquifers, which are underground layers of rock, sand, and gravel that hold water. These underground reservoirs play a crucial role in providing freshwater to communities, agriculture, and industries worldwide.

Surface water, on the other hand, consists of lakes, rivers, and streams, which are visible and more commonly utilized sources of water. While both underground and surface water sources are essential for sustaining life on Earth, it's crucial to understand the vast difference in their quantities to efficiently manage and protect these valuable resources. It is estimated that there is b. 20 to 30 times as much more water stored underground than in all the surface streams and lakes.

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It is important to test the pH directly from the funnel and not the filtrate solution as a whole due to the reason that the filtrate solution may have come into contact with the filter paper, which can change the pH of the solution. Filtration is a process in which a mixture of solid and liquid is separated by passing it through a filter or mesh.

A filter paper is used to separate the liquid and solid particles present in the mixture. The solid particles are collected on the filter paper, while the liquid particles pass through it.What is the significance of testing the pH?pH is a measure of acidity or alkalinity. It determines whether a solution is acidic or alkaline. It is important to test the pH of a filtrate solution to determine the nature of the solution (acidic, neutral, or alkaline).The pH of a solution can be affected by various factors, such as temperature, the presence of acids or bases, etc.

Hence, it is essential to test the pH of a solution to ensure that it is within the required range and does not affect the outcome of the experiment.Why test the pH directly from the funnel It is essential to test the pH directly from the funnel rather than the filtrate solution as a whole to get an accurate reading of the pH of the solution. The filter paper can change the pH of the solution by absorbing some of the acids or bases present in the solution. This can result in an incorrect pH reading of the solution.Therefore, it is crucial to test the pH directly from the funnel to obtain an accurate pH reading and ensure that the experiment's outcome is not affected by any external factors.

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they work less effectively due to the lack of friction on the road when it is wet

pls mark brainliest

Answer: Not really

Explanation: When it's wet, and you slam on the brakes, there's not enough friction with the ground for it to not go spiraling out of control.

Answer:

Because if we do nothing the artic will melt, ocean levels will rise and cause flooding, the earth will be extremely hotter, there will be more blackouts.

Explanation:

The frequency of a wave is speed/wavelength.

Frequency is the number of cycles completed by a wave in one second.

The S.I unit of frequency is hertz.

The formula for the frequency of a wave is given by

Formula:

Where:

Make f the subject of the equation

Hence, The frequency of a wave is speed/wavelength.

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Answer:

C

Explanation:

Trust

Answer:

Alternating current

A wire carries a current of 16 A.

The magnitude of the force on an electron when it is at a distance of 0.06 m from the wire is 5.76 × 10^-12 N.

Wire carries electric current I= 16 A, and is at a distance of r = 0.06m from an electron. The force on the electron is given by the formula;

F = μ0(I1I2)/2πr

Where;

μ0 is the permeability of free space= 4π×10^-7

I1 is the current carried by the wireI2 is the current carried by the electron

F is the force experienced by the electron

In this case, I1 = 16 A, and I2 = 1.6 × 10^-19 C s^-1 (charge on electron)So;

F = (4π×10^-7×16×1.6 × 10^-19)/2π×0.06

F = 5.76 × 10^-12 N

Therefore, the magnitude of the force on an electron when it is at a distance of 0.06 m from the wire is 5.76 × 10^-12 N.

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According to Plumbing 101 principles governing blood flow through the vessels, the statement "Flow depends on pressure difference, but not the absolute pressure" is true.

In the context of Plumbing 101 principles, blood flow through the vessels can be understood by applying the laws of fluid dynamics. According to these principles, the statement that holds true is that flow depends on pressure difference, but not the absolute pressure.

Pressure difference refers to the variance in pressure between two points in a fluid system. In the case of blood flow, it refers to the pressure difference between the point of origin (such as the heart) and the destination point (such as organs or tissues). The pressure difference creates a driving force for blood to flow from higher pressure regions to lower pressure regions.

While the absolute pressure at the origin and destination points may affect the overall pressure difference, it does not directly impact the flow rate of blood. Flow is primarily determined by the pressure difference rather than the absolute pressure at the specific points. Other factors, such as the diameter of the vessel, viscosity of the blood, and the resistance offered by the vessel walls, also influence blood flow.

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The statement that is true about displacement is that displacement may or may not be equal to the distance travelled.

Displacement can be defined as the shortest distance between the initial and the final position of the body.

Displacement is a vector quantity it has a magnitude as well as direction.

Displacement can be zero, can be negative and it also can be positive.

Displacement may or may not be equal to the distance travelled. Because the object travels in the shortest distance possible then the distance will be equal to the displacement of the object. But if the object take any other path to travel from the initial to final position then that is placement may not be equal to the distance travelled.

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Liquid rising in a thermometer as temperature increases is due to the principle of thermal expansion.

The liquid expands as its temperature increases and contracts when cooled. There is an increase in volume temperature except at the phase transition point. This value is called the thermal expansion coefficient.

The material of the glass tube of the thermometer has a very low thermal expansion coefficient, so its internal volume is constant. So on increasing the temperature of the liquid, there is an increase in the volume of the thermometer and an increase in its height in the cylindrical tube.

Since liquids do not have any definite shape and they take the shape of the container in which they are kept, they do not have superficial or linear expansion, they only have volume expansion. So on increasing the temperature of the liquid, its level in the thermometer rises along with the increase in the volume.

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The correct question is:

Why does the liquid rise in a thermometer as temperature increases?

The weight of water displaced by a floating ship is equal to the weight of the ship itself. Since the mass of the ship is 105 kg, we can use the formula weight = mass x gravity, where gravity is 9.8 m/s². Therefore, the weight of water displaced by the ship is 105 x 9.8 = 1,029 N (newtons).

To determine the weight of water displaced by a floating ship whose mass is 105 kg, we can follow these steps:

1. Convert the mass of the ship to weight. Weight (W) can be calculated using the formula W = m × g, where m is the mass of the object (in this case, 105 kg) and g is the acceleration due to gravity (approximately 9.8 m/s²).
W = 105 kg × 9.8 m/s²

W ≈ 1029 N (Newtons)

2. Apply the Archimedes' principle, which states that the buoyant force (B) acting on a floating object is equal to the weight of the fluid displaced by the object. In this case, the buoyant force is equal to the weight of the water displaced.

3. Since the ship is floating, the buoyant force is equal to the weight of the ship. Thus, the weight of the water displaced is also 1029 N. So, the weight of water displaced by the floating ship with a mass of 105 kg is approximately 1029 N.

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No, an object cannot have zero velocity and still be accelerating.

Here are the explanations to support this statement:

Acceleration is the rate at which velocity changes. A change in velocity must occur for an object to accelerate, which implies that the object must be moving (non-zero velocity). Acceleration is a vector quantity, which means that it has both magnitude and direction. An object can have zero acceleration if its velocity is constant (not changing), but it cannot have zero velocity and still be accelerating. For instance, if an object is tossed into the air, it will slow down as it rises to its maximum height, which means that its acceleration is negative (opposite direction to its motion). At the highest point, the velocity of the object is zero, and the acceleration is maximum (g = 9.8 m/s²).

Therefore, if an object has zero velocity, it cannot be accelerating. Acceleration only occurs when velocity changes.

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Answer: b. inversely proportional to each other

Explanation:

The wave with the greatest frequency has the shortest wavelength. Twice the frequency means one-half the wavelength.

Answer: Musical theater is like acting in a musical.

Explanation: Other dance styles don't involve singing.