Why is the efficiency of a machine always less than 100%?

Answer:

they gather information from reflected and absorbed waves.

Explanation:

In a DC generator, the generated electromotive force (emf) is directly proportional to the rotational speed of the generator's armature and the strength of the magnetic field within the generator.

This relationship is described by the equation for the generated emf in a DC generator:

Emf = Φ * N * A * Z / 60

Where:

Emf is the generated electromotive force (in volts),

Φ is the magnetic flux density (in Weber/meter^2\(meter^2\) or Tesla),

N is the number of turns in the armature winding,

A is the effective area of the armature coil (in square meters),

Z is the total number of armature conductors, and

60 is a constant representing the conversion from seconds to minutes.

From this equation, we can see that the generated emf is directly proportional to the magnetic flux density (Φ) and the product of the number of turns (N), effective area (A), and the total number of armature conductors (Z). This means that increasing any of these factors will result in a higher generated emf.

The magnetic flux density (Φ) can be increased by using stronger permanent magnets or increasing the strength of the field windings in the generator.

The number of turns (N) and the effective area (A) are design parameters and can be optimized for a specific generator. Increasing the number of turns or the effective area will result in a higher generated emf.

Similarly, the total number of armature conductors (Z) can be increased to enhance the generated emf.

By controlling and optimizing these factors, the generated emf in a DC generator can be increased, resulting in higher electrical output. However, it is important to note that there are practical limits to these factors based on the design and construction of the generator.

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Answer: 5.08 L.

Explation down below

Thus the response above is correct.

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Answer:

104653.13J

Explanation:

Given parameters:

Mass of roller coaster  = 625kg

Speed  = 18.3m/s

Unknown:

Kinetic energy  = ?

Solution:

The kinetic energy is the energy due to the motion of a body.

     Kinetic energy  = \(\frac{1}{2}\) x m x v²  

m is the mass

v is the speed

    Kinetic energy  =  \(\frac{1}{2}\)  x 625  x  18.3²   = 104653.13J

Answer:

v = 4.0 m/s

Explanation:

       \(p_{f} = m_{w} * v_{w} + m_{g+w} *v_{g+w} = 0 (1)\)

       \(v_{g+w} =- \frac{m_{w} *v_{w}}{m_{g+w} } = - \frac{36.0kg *6.5m/s}{58.0kg } = -4.0m/s (2)\)

Notice that both of those points are 3 units below the x-axis. So the line is horizontal ... its slope is zero.

Answer:

P = d g h         pressure = density * g * depth

P = 1000 kg/m^3 * 9.8 m / s^2 * 1.1 * 10E4 m = 1.1 * 10E8 N/m^2

F = P * A = 1.1 * 10E8 N/m^2 * pi * .075^2 / m^2 = 1.9 * 10E6 N/m^2

The waveform of a signal is the shape of its graph as a function of time in the domains of electronics, acoustics, and allied sciences, regardless of its time and magnitude scales or any shift in time.  

Thus, Waveforms with periodic variations are those that recur consistently at set intervals.

The phrase is typically used in electronics to describe periodically changing voltages, currents, or electromagnetic fields. It is typically used in acoustics to describe constant periodic sounds caused by changes in air pressure or other media.

In these situations, the signal's frequency, amplitude, or phase shift have no bearing on the waveform, which is a characteristic. Additionally, non-periodic signals like chirps and pulses can be referred to by this name.

Thus, The waveform of a signal is the shape of its graph as a function of time in the domains of electronics, acoustics, and allied sciences, regardless of its time and magnitude scales or any shift in time.  

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Answer:

This problem involves the concept of a random walk, which is a mathematical model of a path consisting of a succession of random steps.

The question asks for the distance, R(n), from the center of a star after n steps of a photon, assuming a 2D random walk.

The random walk in two dimensions has a step length of A_i and the direction of the steps is uniformly distributed in [0, 2π). The change in position after each step can be written in Cartesian coordinates (Δx, Δy), where Δx = A_i cos(θ_i) and Δy = A_i sin(θ_i).

The displacement from the center after n steps is given by the vector sum of all the individual steps. This vector sum can be written in terms of its Cartesian coordinates, (X, Y), where X = Σ Δx and Y = Σ Δy. This sum over n random vectors is itself a random variable. The net displacement R(n) from the center of the star after n steps is given by the magnitude of the net displacement vector:

R(n) = √(X² + Y²)

Because each step is independent and has a random direction, the expected value of the cosine and sine for any step is zero. This means that the expected values of X and Y are both zero.

However, the mean square displacement is not zero. Because the steps are independent, the mean square displacement in each direction is additive. For a 2D random walk:

<X²> = Σ <(Δx)²> = n <(A cos θ)²> = n A²/2

<Y²> = Σ <(Δy)²> = n <(A sin θ)²> = n A²/2

Because <X²> = <Y²>, we can write:

<R²> = <X²> + <Y²> = n A²

So, the root mean square distance (the square root of the mean square displacement) after n steps is:

R(n) = √(<R²>) = √(n) * A

Therefore, the distance R(n) that the photon is expected to be from the center of the star after n steps grows as the square root of the number of steps, with each step having a length A. Please note that this result holds for a 2D random walk. A real photon in a star would be performing a 3D random walk, which would have slightly different characteristics.

The total distance covered by the car is 4 kilometers, this is because we are taking into account displacement and not just distance.

Displacement is defined as the change in the position of an object while distance is an object's overall movement in a directionless fashion.

There are many different units that can be used to measure distance (inches, feet, miles, kilometers, and centimeters), but the meter is the SI unit. It is a scalar amount because it does not consider

On the number line, we can see the movement as follows

1 0 -1 -2 -3= 4km

Distance is always positive and never gets smaller as you move. Displacement can be negative, positive, or zero because it refers to the change in the position of an object with respect to its original location.

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The initial volume of the liquid is 31.4 cm³. The volume coefficient of thermal expansion of the liquid is 0.002 per degree Celsius. A temperature increase of 109.5°C is needed for the liquid to rise to a height of 49cm.

The initial volume of the liquid can be found using the formula for the volume of a cylinder:

V = πr²h

where r is the radius (half the diameter), h is the height, and π is approximately 3.14. Plugging in the given values, we get:

V = π(0.5 cm)²(40 cm)

V = 31.4 cm³

The volume coefficient of thermal expansion (β) is defined as the fractional change in volume per degree Celsius change in temperature. It can be calculated using the formula:

β = ΔV/(VΔT)

where ΔV is the change in volume, V is the initial volume, and ΔT is the change in temperature. We can rearrange this formula to solve for ΔV:

ΔV = βVΔT

We know that ΔT = -10°C (a decrease of 10°C) and that the height decreased from 40cm to 37cm, or by 3cm. The change in volume can be found using the formula for the volume of a cylinder again, with the new height of 37cm:

ΔV = π(0.5 cm)²(40 cm - 37 cm)

ΔV = 0.59 cm³

Plugging in all the values, we get:

0.59 cm³ = β(31.4 cm³)(-10°C)

β = 0.002

To find the change in temperature needed for the liquid to rise to a height of 49cm, we can use the same formula as before, but solve for ΔT:

ΔT = ΔV/(βV)

We know that ΔV is the difference between the initial volume and the volume at the new height, which is:

ΔV = π(0.5 cm)²(49 cm - 40 cm)

ΔV = 6.86 cm³

Plugging in all the values, we get:

ΔT = 6.86 cm³/(0.002)(31.4 cm³)

ΔT = 109.5°C

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We have that the  the strength of the force between the Sun and the moon  is mathematically given as

F2=0.12140F1N

Question Parameters:

Distance between the Earth and the Sun were increased by a factor of 2.87,

Generally the equation for the  Gravitational Force   is mathematically given as

\(F=\frac{Gm1m2}{d^2}\\\\Where\\\\f1/f2=d1^2/d2^2\\\\Therefore\\\\F2=\frac{F1*d1}{3.23^2}\\\\F2=\frac{F1*1}{2.87^2}\\\\\)

F2=0.12140F1N

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Answer:

Neurons

Explanation:

1 Newton force is equal to the 10⁻⁵ dynes. The unit of force will be dyne and the value of force will be 0.1 dynes.

Force is defined as the push or pull applied to the body. Sometimes it is used to change the shape, size, and direction of the body. Force is defined as the product of mass and acceleration.

Its SI unit is Newton, MKS unit is kgm/s² and CGS unit is dyne.

The given formulae are;

F = k I l

k is a constant with unit=  N A-1 m-1

I is currently measured in mA = 10⁻³A

l is the length measured in mm= 10⁻³ m

F = k I l

F= N A-1 m-1× 10⁻³A×10⁻³ m

F= 10⁻⁶ N                 ( 1N = 10⁻⁵ dyne)

F= 0.1 dyne

Hence the unit of force will be dyne and the value of force will be 0.1 dynes.

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The pressure at the upper level of a water flow into the house by means of pipe is 1081 kPa.

Calculate the cross-sectional area of the lower pipe:

A₁ = πr₁²

where:

A₁ = cross-sectional area of the lower pipe (m²)

π = mathematical constant (3.14)

r₁ = radius of the lower pipe (m)

A₁ = π(0.12 m)² = 0.0452 m²

Calculate the cross-sectional area of the upper pipe:

A₂ = πr₂²

where:

A₂ = cross-sectional area of the upper pipe (m²)

π = mathematical constant (3.14)

r₂ = radius of the upper pipe (m)

A₂ = π(0.06 m)² = 0.0113 m²

Calculate the flow rate per unit area:

q = Q/A

where:

q = flow rate per unit area (m³/s)

Q = flow rate (m³/s)

A = cross-sectional area (m²)

q = 6 m³/s / 0.0452 m² = 13.28 m²/s

Calculate the velocity of the water in the lower pipe:

v₁ = q/A₁

where:

v₁ = velocity of the water in the lower pipe (m/s)

q = flow rate per unit area (m³/s)

A₁ = cross-sectional area of the lower pipe (m²)

v₁ = 13.28 m²/s / 0.0452 m² = 29.3 m/s

Calculate the velocity of the water in the upper pipe:

v₂ = q/A₂

where:

v₂ = velocity of the water in the upper pipe (m/s)

q = flow rate per unit area (m³/s)

A₂ = cross-sectional area of the upper pipe (m²)

v₂ = 13.28 m²/s / 0.0113 m² = 117.0 m/s

Calculate the head loss:

hL = (v₁² - v2₂²) / 2g

where:

hL = head loss (m)

v₁ = velocity of the water in the lower pipe (m/s)

v₂ = velocity of the water in the upper pipe (m/s)

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

hL = (29.3 m/s)² - (117.0 m/s)² / 2(9.8 m/s²) = 23.2 m

Calculate the pressure at the upper level:

p₂ = p₁ + ρghL

where:

p₂ = pressure at the upper level (Pa)

p₁ = pressure at the lower level (Pa)

ρ = density of water (1000 kg/m³)

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

hL = head loss (m)

p₂ = 400 kPa + 1000 kg/m³(9.8 m/s²)(23.2 m) = 1081 kPa

Therefore, the pressure at the upper level is 1081 kPa.

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Answer:

Yes

Explanation:

But I feel also 2 is correct but your answer is right

Mass of the second object located at a distance r from the origin, r^ is the unit vector in the radial direction, and the negative sign indicates that the force

The System can refer to a set of interacting or interdependent components forming an integrated whole. The term can be applied to various fields, including physics, engineering, biology, and social sciences, among others. In physics, a system typically refers to a collection of objects or particles that are studied together, often with the goal of understanding the behavior of the system as a whole. In engineering, a system can refer to a group of components that work together to perform a specific function, such as an electrical power grid or an automobile engine. In biology, a system can refer to an organism or group of organisms that interact with their environment, such as an ecosystem or the human body.

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Given:

The energy difference, E=2.4 eV

To find:

The wavelength of the emitted line.

Explanation:

The energy of the wave emitted will be equal to the energy difference between the two energy levels.

The energy of the wave is given by the equation,

Where h is the Plank's constant and c is the speed of light.

The energy in joules is given by,

On substituting the known values in the equation of the energy,

Final answer:

Thus the wavelength of the line is 517.7 nm

Answer:

It will take 15 seconds

A hollow glass sphere has a density of 1.3g/cm at 20 C. Glycerine has a density of 1.26 g/cm at 20 C.

To determine the temperature at which the hollow glass sphere begins to float in glycerine, we need to calculate the density of glycerine at various temperatures and compare it to the density of the glass sphere.

The density of glycerine changes with temperature, so we need to use a density-temperature chart or equation to determine the density of glycerine at different temperatures.

Assuming the hollow glass sphere has a uniform wall thickness, we can calculate its volume by subtracting the volume of the hollow interior from the volume of the whole sphere

Volume of sphere = (4/3)π\(r^{3}\)

Volume of hollow interior = (4/3)π\((r-t)^{3}\)

Volume of glass wall = (4/3)π(\(r^{3}\) - \((r-t)^{3}\)), where t is the thickness of the glass wall.

From the density and volume of the glass sphere, we can determine its mass

Mass of glass sphere = Density of glass sphere x Volume of glass sphere

Next, we can use Archimedes' principle to determine the volume of glycerine displaced by the glass sphere when it is submerged in the glycerine

Volume of glycerine displaced = Mass of glass sphere / Density of glycerine at the given temperature

When the glass sphere floats, the volume of glycerine displaced will be equal to the volume of the glass sphere. Thus, we can set the two volumes equal to each other and solve for the temperature at which the density of glycerine matches the density of the glass sphere

Volume of glass sphere = Volume of glycerine displaced

(4/3)π\(r^{3}\) - (4/3)π\((r-t)^{3}\) = Mass of glass sphere / Density of glycerine at the given temperature

Hence, for the temperature requires knowing the radius and thickness of the glass sphere and the mass of the sphere.

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The temperature of the air mass when it has risen to a level at which atmospheric pressure is only 8.70×10⁴ Pa is approximately 14.3°C.

Using the ideal gas law, we can write: PV = nRT, where P is the pressure, V is the volume, n is the number of moles of gas, R is the gas constant, and T is the absolute temperature. Since the mass of air is not changing, we can write: PV = constant.

Applying this to the situation where the air mass rises to a level where the pressure is 8.70×10⁴ Pa, we get:

Dividing the second equation by the first and using the fact that γ=Cp/Cv=1.40 for air, we get:

Solving for T2, we get:

Thus, the temperature of the air mass when it has risen to a level at which atmospheric pressure is only 8.70×10⁴ Pa is approximately 14.3°C.

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Answer:

C

Explanation:

The thermal energy from her hand will go up into the smoothie.

Answer:

C bois

Explanation:

Net force applied on the soccer ball was approximately 250 N (newtons) when it was kicked by the player.

We use Newton's second law of motion, which states that net force (F_net) applied to an object is equal to the product of its mass (m) and acceleration (a):

F_net = m * a

In this case, mass of the soccer ball is given as  0.5 kg and the acceleration is 500 (m)/(s²), so:

F_net = 0.5 kg * 500 (m)/(s²) = 250 N

Therefore,  net force applied on the soccer ball was approximately 250 N (newtons) when it was kicked by the player.

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Answer:

Using the pythagoras theorem

S²=9²+4²

S²=81+16

S²=97

S=9.85km.

In finding the direction

tan□=opposite/Adjacent

=4/9

□=23.96

¤=90-23.96

=66.03 degrees

9.85, N 66.03 E

The scientific method include Observations >> Data; Factor manipulated >> Independent Variable, process to test >> experiment, guess >> hypothesis, results >> Conclusion and response >> dependent variable.

Observation is the first step of the scientific method, which then requires to raise a question that will be answered by a testable hypothesis.

The scientific method is a series of well-established steps used to collect scientific empirical data/evidence, which allow to test a given hypothesis.

In conclusion, the scientific method include Observations >> Data; Factor manipulated >> Independent Variable, process to test >> experiment, guess >> hypothesis, results >> Conclusion and response >> dependent variable..

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According to the question the distance between the object A and the image 1₂ is 6 cm.

Distance is the measure of how far apart two objects, points, or locations are from one another. Distance can be measured in linear units such as feet, meters, or kilometers, or angular units such as degrees. The concept of distance is a fundamental concept in mathematics, physics, and other sciences. Distance is used to calculate the speed and velocity of objects, as well as the force of gravity between two objects.

The distance between the object A and the image 1₂ can be calculated using the mirror equation.

Mirror equation: 1/d₁ + 1/d₂ = 1/f

Where d₁ is the object distance, d₂ is the image distance, and f is the focal length of the mirror.

In this case, d₁ = 12 cm, d₂ = ? and f = 8 cm.

Substituting these values into the equation gives us:

1/12 + 1/d₂ = 1/8

Rearranging the equation gives us:

1/d₂ = 1/8 – 1/12

Plugging in the values gives us:

1/d₂ = 1/8 – 1/12 = 1/6

Solving for d₂ gives us:

d₂ = 6 cm

Therefore, the distance between the object A and the image 1₂ is 6 cm.

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Although it is true that scientific models and hypotheses have been updated and improved over time, this is not sufficient justification to reject science as a whole or to doubt what scientists claim.

Models aid in our comprehension of systems and their characteristics. An atomic model, for instance, depicts what an atom's structure may like based on what is known about how atoms function. It may not accurately represent the precise makeup of an atom. Models are frequently condensed.

Over time, this atomic model has evolved. The model was used by scientists to make predictions. Their trials occasionally yielded unexpected outcomes that did not match the pre-existing model. The model was modified by scientists so that it could account for the fresh data.

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Newton's Law of Cooling states that the rate of cooling of an object is proportional to the temperature difference between the object and its surroundings.

dQ/dt = -k(T - Troom)

where Q is the amount of heat in the water, t is time, k is a constant, T is the temperature of the water, and Troom is the room temperature.

Using the given information, we can set up the following system of equations:

100 = k(100 - 21) (at t = 0) 65 = k(100 - 21) e⁽⁻¹⁰⁾k (at t = 10)

Solving for k in the first equation gives k = 1/79. Plugging this value into the second equation and solving for T gives T = 36.1 degrees Celsius.

Now, to find the temperature after an additional 5 minutes, we can use the same equation with a new time value:

T = (65 - Troom) e^(-k(10+5)) + Troom

Plugging in the values we know gives T = 30.4 degrees Celsius.

Therefore, the temperature of the water after an additional 5 minutes of cooling is approximately 30.4 degrees Celsius

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