why are circuit breakers used in parts of national grid ?

Answers

Answer 1

Answer:

To protect control circuits or small devices with insufficient cutting power

Explanation:


Related Questions

Find the emitted power per square meter and wavelength of peak intensity for a 3000 K object that emits thermal radiation.

Answers

Answer:

power per square meter = 4.593 × 10^(6) W/m²

Wavelength of peak intensity = 9.67 × 10^(-7) m

Explanation:

From Stefan-Boltzmann law, total emitted power per square meter is given as;

P/A = eσT⁴

where;

P is power

A is surface area

σ = Stefan-Boltzmann constant = 5.67 × 10^(-8) W/m².k⁴

T = temperature of the body = 3000 K

e = emissivity of the substance (for ideal radiation, it has a value = 1)

Thus, Plugging in the relevant values we have;

P/A = 1 × 5.67 × 10^(-8) × (3000)^(4)

P/A = 4.593 × 10^(6) W/m²

Let's find the wavelength of peak intensity.

From wiens displacement law, we know that;

λ_m × T = b

where;

λ_m = maximum wavelength

T = Temperature

b is Wien's displacement constant = 2.9 × 10^(−3) m/K

thus;

λ_m = b/T = (2.9 × 10^(−3))/3000 = 9.67 × 10^(-7) m

Señalar la importancia de las capacidades fisico-motiz que se desarrollan en el futbol de salon y dar un ejemplo para cada uno

Answers

La respuesta correcta para esta pregunta abierta es la siguiente.

A pesar de que no anexas opciones o incisos para responder, podemos comentar lo siguiente.

La importancia de las capacidades físico-motriz que se desarrollan en el futbol de salón son determinantes para desarrollar o maximizar las actividades propias de este deporte con objeto de rendir al máximo y aspirar al mejor de los resultados.

Estas capacidades físico-motrices son las que le permiten a un jugador realizar su máximo esfuerzo, mejorar su desempeño físico y conseguir resultados positivos.

Estamos hablando de la fuerza, la velocidad y la resistencia.

La velocidad es la aceleración que el jugador de futbol necesita para aumentar su velocidad de un punto A, a un punto B, en el menor tiempo posible.

La resistencia es la capacidad del jugador de futbol para mantener ese nivel de aceleración y desempeño, sin bajar su rendimiento. Su capacidad física debe ser resistente para ser constante en su rendimiento físico.

La fuerza es la potencia con la que desempeña los movimiento físicos dentro de la cancha.

A HIGH SPEED TRAIN IS 180M LONG AND IT IS TRAVELLING AT 50M/S.HOW LONG WILL IT TAKE TO PASS A PERSON STANDING AT A LEVEL CROSSING?



B-HOW LONG WILL IT TAKE TO PASS COMPLETELY THROUGH A STATION WHOSE PLATFORMS ARE 220M IN LENGTH?

Answers

Answer:

a. Time = 3.6 seconds

b. Time = 4.4 seconds

Explanation:

Given the following data;

Distance = 180 m

Speed = 50 m/s

a. To find the time;

Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.

Mathematically, speed is given by the formula;

[tex]Speed = \frac{distance}{time}[/tex]

Making time the subject of formula, we have;

[tex]Time = \frac{distance}{speed}[/tex]

Substituting into the equation, we have;

[tex]Time = \frac{180}{50}[/tex]

Time = 3.6 seconds

b. Distance = 220 meters

Speed = 50 m/s

To find the time;

[tex]Time = \frac{distance}{speed}[/tex]

Substituting into the equation, we have;

[tex]Time = \frac{220}{50}[/tex]

Time = 4.4 seconds

The circuit diagram below shows the locations of four switches. Which
switch configuration creates a short circuit?
fo
W
WT

Answers

Answer:

C option

Explanation:

Hope this helps... pls vote as brainliest

pleaase help me i don't know this !!!

Answers

Answer:

coefficient=1.09N/m×g

coefficient=1.09N/0.413g×10m/s square

coefficient=1.09N/4.13N

coefficent=0.263

f= uK

here f is force, u is cofficient of friction , k is normal force

k = mg

f = umg

1.09 = u × 0.41 × 10

u = 1.09 ÷ 4.1

u = 0.26

Accelaration is a derived quantity .Give reason

Answers

Answer:

The accerlation is a derived from the other quantities like change in velocity/time take etc.


Spending more time with her grandchildren is most likely a short-term goal
for a person of which of these ages?
A. 20 years old
B. 10 years old
C. 30 years old
D. 60 years old

Answers

Answer:60

Explanation:

I think it’s D but I am not sure

IV. The table below shows how the speed of a car changes with time. 1 What is the acceleration of the car? please help! :(​

Answers

Acceleration = change in velocity/ time

So I believe that the change in velocity will be 20-0 which is 20

And the time will be 5

Therefore 20/5 so the acceleration will be 4

A car starts from rest. if rhe final velocity becomes 50m /s after 10 second calculate the acceleration of the car.​

Answers

Answer:5m/s² well I am not pretty sure but hope it's help

Explanation:

u=0m

final velocity ,v=50m/s

t=10s

(v-u)/t=(50-0)/10=50/10=5m/s²

Which has greater kinetic energy, a car traveling at 40 mph or a half-as-massive car traveling at 80 mph?
a
-The 40 mph car
-The 80 mph car
-Both have the same kinetic energy
-Neither has kinetic energy

Answers

Answer:

The 80 mph car

Because the formula says 1/2 mass but for the velocity it is squared

(x – 2)² = 5(y + 1), where x and y are measured in centimeters. You need to place a new light bulb in your flashlight. How far away from the vertex of the parabolic mirror should you place the bulb to ensure a perfect beam of light? The bulb should be placed .

Answers

Answer:

The coordinates of the point the bulb should be placed is (2, 0.25)

Explanation:

The given equation of a parabola is presented as follows;

(x - 2)² = 5·(y + 1)

The point the bulb should be placed is the focus of the parabolic mirror to ensure a perfect (straight) beam

The general form of the equation of a parabola is (x - h)² = 4·p·(y - k)

The coordinates of the focus of the parabola for p > 0 f = (h, k + p)

By comparison, h = 2, k = -1, and p = 5/4

∴ The coordinates of the focus of the parabola, f = (2, -1 + 5/4)  = (2, 0.25)

The coordinates of the point the bulb should be placed is at the focus, f =  (2, 0.25).

Select the correct answer.
Which quantity is a vector quantity?
ОА. .
acceleration
OB.
mass
OC.
speed
O D.
volume
Reset
Next

Answers

Answer:

acceleration is the vector quantity because it depends on particular direction and has magnitude

"" damped force equation ""​

Answers

Answer:

In many vibrating systems the frictional force Ff can be modeled as being proportional to the velocity v of the object: Ff = −cv, where c is called the viscous damping coefficient.

I need help answer these questions please

Answers

Answer:

1. 25 J

2. 250 J

3. 900,000 J

4. 7,500 J

Explanation:

1. The distance the wheelbarrow is tilted, d = 0.5 m

The force used to tilt the wheelbarrow, F = 50 N

The work done, W = F × d

∴ W = 50 N × 0.5 m = 25 J

2. Work done, W = Force × Distance

The applied force, F = 50 N

The distance the sand is moved, d = 5 m

∴ W = 50 N × 5 m = 250 J

3. The work done, W = The load lifted × The height to which the load is lifted

∴ W = 90,000 N × 10 m = 900,000 J

The work done, W = 900,000 J

4. The work output of the skateboard = The work input × Efficiency

Given that the skateboard is an ideal machine, we have;

The work output of the skateboard = The work input = W

W = F × d

F = 15 N, d = 500 m

∴ W = 15 N × 500 m = 7,500 J

The work output of the skateboard = W = 7,500 J.

the ratio of the energy per second radiated by the filament of a lamp at 250k to that radiated at 2000k, assuming the filament is a blackbody radiator? The filament of a particular electric lamp can be considered as a 90%blackbody radiator. calculate the energy per second radiated when its temperature is 2000k if its surface area is 10∧-6 m²

Answers

Answer:

(a) [tex]\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]

(b) P =  0.816 Watt

Explanation:

(a)

The power radiated from a black body is given by Stefan Boltzman Law:

[tex]P = \sigma AT^4[/tex]

where,

P = Energy Radiated per Second = ?

σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴

T = Absolute Temperature

So the ratio of power at 250 K to the power at 2000 K is given as:

[tex]\frac{P_{250k}}{P_{2000k}}=\frac{\sigma A(250)^4}{\sigma A(2000)^4}\\\\\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}[/tex]

(b)

Now, for 90% radiator blackbody at 2000 K:

[tex]P = (0.9)(5.67\ x\ 10^{-8}\ W/m^2.K^4)(1\ x\ 10^{-6}\ m^2)(2000\ K)^4[/tex]

P =  0.816 Watt

a student drops a ball off the top of building and records that the ball takes 3.32s to reach the ground (g=9.8 m/s^2). what is the ball's speed just before hitting the ground?​

Answers

Answer:

Explanation:

Use the one-dimensional equation for motion

v = v₀ + at and filling in,

v = 0 + (-9.8)(3.32) so

v = -33 m/s (negative because it is going downwards and upwards is positive).

Object A has twice the mass of object B. Both objects are moving at the same speed. Which accurately describes how inertia relates to Newton’s second law of motion in this example? Object A has twice the mass of object B. Both objects are moving at the same speed.

A. Object A requires twice the force to stop as Object B.

B. Object A requires one-and-a-half times the force to stop as Object B.

C. Object A requires four times the force to stop as Object B.

Answers

Answer:

A. Object A requires twice the force to stop as Object B.

Explanation:

Inertia can be defined as the tendency of an object or a body to continue in its state of motion or remain at rest unless acted upon by an external force.

Newton's Second Law of Motion states that the acceleration of a physical object is directly proportional to the net force acting on the physical object and inversely proportional to its mass.

Mathematically, it is given by the formula;

[tex] Acceleration = \frac {Net \; force}{mass} [/tex]

Let's assume the following values;

Mass of object B = 10 kg

Mass of object A = 2 * B = 2 * 10 = 20 kg

Acceleration = 5 m/s²

I. To find the force for B;

[tex] Force = mass * acceleration [/tex]

[tex] Force = 10 * 5 [/tex]

Force B = 50 Newton

II. To find the force for A;

[tex] Force = mass * acceleration [/tex]

[tex] Force = 20 * 5 [/tex]

Force A = 100 Newton

From the calculation, we can deduce that Force A (100 N) is twice or double the value of Force B (50 N).

In conclusion, since object A has twice the mass of object B and both objects are moving at the same speed, object A would require twice the force to stop as Object B.

what is meant by fundamental unit? write any two difference between mass and weight.​

Answers

Answer:

Fundamental unit is any unit that is not dependent on other units and other units can be derived from them

Explanation:

Units such as Kilogram, Mass and Time are said to be fundamental units because they are independent.

Differences between Mass and weight;

1. Mass is the measure of the amount of matter in a body while weight is a measure of how the force of gravity acts upon that mass.

2. Mass is a scalar quantity while weight is a vector quantity

The drone can fly for 25 minutes before the battery needs recharging.
The power output of the battery is 65.0 W
Calculate the maximum energy stored by the battery.

Answers

Answer:

105.6 KJ

Answer

3.7/5

4

hope this will help you friend.

Um comentarista de futebol certa vez comentou:"A bola bateu na trave e voltou duas vezes mais forte". Sabendo que quando a bola atinge a trave ela acerta com uma força chamada de ação e a outra trave acerta com outra força chamada de reação explique porque a frase documentalista soa errada.

Answers

Answer:

Por ela ter batido na trave, não tem como voltar 2x mais forte, por que toda ação correspondente a uma reação de igual intensidade, mas que atua no sentido oposto

Explanation:

1. The electromagnetic spectrum is the range of all types of radiation.
a. index of refraction
b. EM
c. laser

Answers

Answer:

EM

Explanation:

The index of refraction is a special property that shows how light travels through different medias. It does not concern itself with the spectrum, only what it will do to that spectrum under laboratory conditions.

Laser light is a very narrow concentrated light form. It is not the entire spectrum, but only a very small part of it.

The answer you want is EM Electromagnetic Radiation

calculate the voltage applied to 2.00

Answers

Answer:

Here is your answer

Explanation:

1.55 V is the answer

hope u like it

A cheetah runs at a speed of 27.6 m/s. If the
cheetah runs for 9.30 s, what is the distance the
cheetah runs? Show all your work.

Answers

Answer:

256.68m

Explanation:

that is the procedure above

A cheetah runs at a speed of 27.6 m/s. If the cheetah runs for 9.30 s, then the distance covered by the cheetah would be 256.68 metes

What is speed?

The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is meter/second. The generally considered unit for speed is a meter per second.

The mathematical expression for speed is given by

speed = distance /Total time

As given in the problem A cheetah runs at a speed of 27.6 m/s. If the cheetah runs for 9.30 s, we have to calculate the distance covered by the cheetah

Distance=?

speed=27.6 m/s

time= 9.30 s

speed = distance /Total time

27.6 m/s = Distance /9.30 s

Distance = 27.6×9.30

               =256.68 metes

Thus, the distance covered by the cheetah would be 256.68 metes

Learn more about speed from here

brainly.com/question/7359669

#SPJ5

b) A stone floor feels very cold to bare feet in winter, but a carpet in
the same room feels comfortably warm. Why is this?

Answers

Answer:

A stone floor feels very cold to bare feet in winter, but a carpet in the same room feels comfortably warm.This is because both the floor and the carpet have the same temperature as both are exposed to the same atmosphere. But the former conducts away the heat from the feet better than the carpet as the latter is a non-conductor. So the feet losing more heat, the floor appears cooler to the feet

Explanation:

Hope it may help you!!

Both actually have same temperature. Our feet are warm. Floor is conductor of heat while carpet is not. When we walk on floor, then floor takes away or conducts the heat from our feet, so we feel cold. While carpet doesn't do that, so we feel warm.

A train starts from rest and leaves Greenburg station with an acceleration of 1.20 meters per second2. How long does it take the train to travel a distance of 500 meters?

Answers

Answer:

Time, t = 28.87 seconds

Explanation:

Given the following data;

Acceleration = 1.20 m/s²

Distance = 500 meters

Initial velocity = 0 m/s

To find the time to cover the distance, we would use the second equation of motion;

[tex] S = ut + \frac {1}{2}at^{2}[/tex]

Where;

S represents the displacement or height measured in meters.

u represents the initial velocity measured in meters per seconds.

t represents the time measured in seconds.

a represents acceleration measured in meters per seconds square.

Substituting into the equation, we have;

[tex] 500 = 0*t + \frac {1}{2}*(1.2)*t^{2}[/tex]

[tex] 500 = 0 + 0.6*t^{2} [/tex]

[tex] 500 = 0.6t^{2} [/tex]

[tex] t^{2} = \frac {500}{0.6} [/tex]

[tex] t^{2} = 833.33 [/tex]

Taking the square root of both sides, we have;

[tex] t = \sqrt{833.33} [/tex]

Time, t = 28.87 seconds

A room has a rectangular shape of 4000 mom by 3600mm according to the architecture plan It is supposed to be fitted with tiles which are square in shape and size of 12 cm. How many tiles are required to cover the entire floor​

Answers

Explanation:

First find the area of the entire floor:

Area of a rectangle= length × width

( 4000mm× 3600mm)

14400000mm²

Area of one square tile??= side ×side

12cm×12cm

144cm²

Convert cm to mm

1cm²=100mm²

144cm²=144cm²/1cm²×100mm²

=14,400mm²

Number of tiles required to cover the entire floor= 14400000mm²/14400mm²

=1000

A constant unbalanced force is applied to an object for a period of time. What will happen to the objects acceleration?

a. It will accelerate in the direction of the net force.
b. It will accelerate opposite the direction net force.
c. There is no acceleration.
d. Not enough information to answer

Answers

Answer:

A

Explanation:

The moving object will accelerate as long as a net force is applied. If a net force is not applied, the object will continue to move at a constant speed along the same path in curved spacetime (due to gravity). If the net force continues the velocity of the object will continue to increase until nearly reaching the limit (speed of light).

Two tuning forks, 492 Hz and 498 Hz, are struck simultaneously. How many beats will be heard?

none
2.00 beats
4.00 beats
6.00 beats

Answers

Answer:

6 beats

If one fork beats once and another twice in the same time period

you would hear 1 beat. (Same for 2 and 3 beats).

PLEASEE HELPP!!!
Describe melting.
Describe evaporation.
Describe boiling.
Describe condensation.
Describe freezing.

Answers

Melting: the substance changes back from the solid to the liquid

Evaporation: the process by which water changed from a liquid to a gas.

Boiling: the process by which a liquid turns into a vapor when it is heated to it's boiling point.

Condensation: the substance changed from a gas to a liquid

Freezing: the substance changed from a liquid to solid.

Answer:

Melting is a process that causes a substance to change from a solid to a liquid.

Evaporation is the process of turning from liquid into vapour.

Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the

Condensation is the process of water vapor turning back into liquid water

Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point

when is the acceleration of body is positive negative and zero?​

Answers

Answer:

【 In vector form , if angle between velocity vector and acceleration vector is less than 90° and greater than 0° then it is positive acceleration and if it is less than 180° and greater than 90° then it is negative acceleration. If there is no acceleration vector then it is called zero acceleration. 】

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