Câu 9. Một dây dẫn đồng chất, tiết diện đều 20mm2 có dòng điện không đổi 12A đi qua. Tính trị trung bình mật độ dòng điện j ?

Answers

Answer 1

Answer:

Sorry I can't understand you


Related Questions

Please write a paragraph explaining the bible verse below in your own words.


Exodus 16:1-3

Answers

Answer: Moses

Explanation: The Israelites are angry at Aaron and Moses, because they lead them into this desert where there is no food, or water. It was told that after the Israelites left Egypt they would wander the desert for forty years. The Israelites complain that they would have had plenty of food if they had just stayed enslaved in Egypt. They are not grateful that God has liberated them from slavery.

7 A 0.25 kg block oscillates on the end of a spring with a spring constant of 100 N/m. If the oscillation is started by elongating the spring 0.1m and giving the block a speed of 3 mis then the amplitude of the oscillation is:​

Answers

(K+U)
i

=(K+U)
f



0+
2
1

kA
2
=
2
1

mv
2
+
2
1

kx
2



2
1

(6.50 N/m)(0.100 m)
2
=
2
1

m(0.300 m/s)
2
+
2
1

(6.50 N/m)(5.00×10
−2
m)
2


3.25×10
−2
J=
2
1

m(0.300 m/s)
2
+8.12×10
−3
J

giving m=
9.0×10
−2
m
2
/s
2

2(2.44×10
−2
J)

=
0.542 kg



(b) ω=
m
k



=
0.542 kg
6.50 N/m



=3.46 rad/s

Then, T=
ω


=
3.46 rad/s
2π rad

=
1.81 s



(c) a
max

=Aω
2
=(0.100 m)(3.46 rad/s)
2
=
1.20 m/s
2

How can gravity's role in tectonic plate motion be described?

Answers

Answer: In ridge push, the mantle wells upward because of the convection and elevates the edges of spreading oceanic plates. Because these plates are higher at the spreading center, they are forced downhill due to gravity and eventually flatten out to the ocean floor.

the answer I need points for my math test

True or false. The buildings in cities are getting larger

Answers

Answer:

true

Explanation:

cuase the city is getting more people than before

A hot air balloon rising vertically is tracked by an observer located 2 miles from the lift-off point. At a certain moment, the angle between the observer's line-of-sight and the horizontal is , and it is changing at a rate of 0.1 rad/min. How fast is the balloon rising at this moment

Answers

We have that for the Question, it can be said that

the balloon rising at [tex]0.266miles/min[/tex]

From the question we are told

An observer located 2 miles from the lift-off point. At a certain moment, the angle between the observer's line-of-sight and the horizontal is , and it is changing at a rate of 0.1 rad/min.

From,

[tex]tan\theta = \frac{h}{2}[/tex]

differentiate with respect to h

[tex]sec^2\theta * \frac{do}{dz} = \frac{1}{2} * \frac{dh}{dz}\\\\\frac{dh}{dz} = 2 sec^\theta * \frac{d\theta}{dz}\\\\\theta = \frac{\pi}{6} and \frac{d\theta}{dz} = 0.1rad/min\\\\\frac{dh}{dz} = 2sec^2 (\frac{\pi}{6}) * (0.1)\\\\= 0.266miles/min[/tex]

For more information on this visit

https://brainly.com/question/23379286

A 770-kg two-stage rocket is traveling at a speed of 6.90×103 m/s away from Earth when a predesigned explosion separates the rocket into two sections of equal mass that then move with a speed of 2.60×103 m/s relative to each other along the original line of motion.What is the speed of each section (relative to Earth) after the explosion?How much energy was supplied by the explosion?

Answers

Answer:

Explanation:

Let's just have our reference frame travel along with the original un broken mass. This way the original velocity is not relevant.

Each half will have a mass of 770/2 = 385 kg

Each half will have the same magnitude of velocity (conservation of momentum) which will be 2.6 x 10³/2 = 1.30 x 10³ m/s

Now add back the reference frame velocity to get velocity relative to earth.

Section one will have velocity 6.90 x 10³ + 1.30 x 10³ = 8.2 x 10³ m/s

Section two will have velocity 6.90 x 10³ - 1.30 x 10³ = 5.6 x 10³ m/s

In the moving reference frame, each half will have kinetic energy which could only come from the explosion

KE = ½(385)(1.3 x 10³)² = 325,325,000 J

2(325,325,000) = 650,650,000 J released in the explosion.

Rounding to the three significant figures of the problem numerals

E = 6.50 x 10⁸ J or 650 MJ released

An object is moving due north at 31m/s. Does this tell you the speed of the velocity of the object or both?

Answers

Answer:

speed

Explanation:

its the speed

because the formula for deriving speed is distance/time

the unit for distance is metre

the unit for time is seconds

so speed is metre/seconds

so speed us m/s.

PLEASE PLEASE HELP!!

An arrow is shot straight up in the air from the ground with an initial velocity of 54.0 m/s. If on striking the ground it
embeds itself 15.0 cm into the ground, what is the acceleration required to stop the arrow when it hits the ground?

Answers

Answer:

you have patience the distance.

Explanation:

the train leaves at 6.30.

A car drives at a constant speed of 45km in 20mn. The speed of the car is..?​

Answers

Answer:

83.8851 mi/h              

An airplane has a mass of 33,000 kg and takes off under the influence of a constant net force of 44,000 N. What is the net force that acts on the plane's 70 kg pilot

Answers

Answer:

Explanation:

acceleration a = F/m = 44000/33000 = 1.3m/s²

F = ma = 70(1.3) = 93 N

Define average atomic mass and explain how it is calculated

Answers

Answer:

The average atomic mass of an element is the sum of masses of it's isotopes

Each are multiplied by it's natural abundance

Explanation:

The average atomic mass of an element is the sum of masses of it's isotopes

Each are multiplied by it's natural abundance

PLEASE HELP!!!


If a 40cm rope with a 220g bob can hold a maximum tension of 3N
a) what are the maximum angular velocity and inclination angle it can reach before the rope break?
b) Angle of inclination​

Answers

Answer:

ω = 3.1 rad/s

θ = 36° from vertical

Explanation:

I will ASSUME that the bob and string is acting as a pendulum.

Please understand that the string will break when the bob is at the lowest point of the swing where the vectors of gravity and centripetal acceleration align. It will NOT break at the angle of maximum inclination measured from vertical. This angle is only a component of the maximum potential energy that gets converted to maximum kinetic energy at the lowest point of the swing.

At the bottom of the swing, the string must support the weight of the bob plus supply the required centripetal acceleration.

F = mg + mω²R

F/m = g + ω²R

F/m - g = ω²R

ω = √((F/m - g)/R)

ω = √((3/0.220 - 9.8)/0.40)

ω = 3.09691...

ω = 3.1 rad/s

Potential energy will convert to kinetic energy

       mgh = ½mv²

             h = v²/2g

R - Rcosθ = v²/2g

R(1 - cosθ) = v²/2g

   1 - cosθ = v²/2gR

        cosθ = 1 - v²/2gR

        cosθ = 1 - (Rω)²/2gR

        cosθ = 1 - Rω²/2g

        cosθ = 1 - 0.40(3.1²)/(2(9.8))

        cosθ = 0.804267

              θ = 36.46045...

              θ = 36°

A bear slides down an incline which is oriented at 17 degrees above horizontal. What is the coefficient of friction between the bear and the incline if the bear moves with a constant velocity?

Answers

[tex]\mu = 0.306[/tex]

Explanation:

Assume that the direction down the incline is the +x-direction. We can apply Newton's 2nd law along the x-axis as

[tex]x:\:\:\:\:\:mg\sin17° - f_s = ma[/tex]

[tex]\Rightarrow mg\sin17° - \mu N = 0[/tex]

where m is the mass of the bear and g is the acceleration due to gravity and acceleration a is zero since the bear is moving with a constant velocity. Along the y-axis, we can write Newton's 2nd law as

[tex]y:\:\:\:\:\:N - mg\cos17° = 0 \Rightarrow N = mg\cos17°[/tex]

Combining these two equations together, we get

[tex]mg\sin17° = \mu(mg\cos17°)[/tex]

Solving for [tex]\mu, [/tex]

[tex]\mu = \dfrac{\sin17°}{\cos17°} = \tan17° = 0.306[/tex]

50 points help

Column I Column II

______ 1. acceleration a. change in distance over time

______ 2. speed b. time interval

______ 3. velocity c. scalar

______ 4. Δt. d. change in position

______ 5. Magnitude only e. change in velocity over time

______ 6. Δx f. change in displacement over time

Answers

[tex]\\ \sf\longmapsto Acceleration\longrightarrow Change\:in\: Velocity\:over\:time[/tex]

[tex]\\ \sf\longmapsto Speed\longrightarrow Change\:in\: Distance\:over\:Time[/tex]

[tex]\\ \sf\longmapsto Velocity\longrightarrow Change\:in\: Displacement\: over\:time[/tex]

[tex]\\ \sf\longmapsto ∆t\longrightarrow Time\: interval [/tex]

[tex]\\ \sf\longmapsto Magnitude\:only\longrightarrow Scaler[/tex]

[tex]\\ \sf\longmapsto ∆x=Change\:in\: position [/tex]

The figure shows the light intensity on a screen behind a double slit. The slit spacing is 0.22 mm and the screen is 2.0 m behind the slits (Figure 1). What is the wavelength of the light?

Answers

The wavelength of the light is 550 nm

For a double slit interference pattern with slit spacing, d we have

dsinθ = mλ where d = slit spacing = 0.22 mm = 0.22 × 10⁻³ m, m = number of maximum fringe = 2(from the picture) and λ = wavelength of light.

Thus sinθ = mλ/d

Also, tanθ = L/D where L = distance between central maximum and fringe = 2.0 cm/2 = 1.0 cm = 1 × 10⁻² m and D = distance between slit and screen = 2.0 m

Since θ is small, sinθ ≅ tanθ

So, mλ/d = L/D

Making λ subject of the formula, we have

λ = dL/mD

Substituting the values of the variables into the equation, we have

λ = dL/mD

λ = 0.22 × 10⁻³ m × 1 × 10⁻² m/(2 × 2.0 m)

λ = 0.22 × 10⁻⁵ m²/4.0 m

λ = 0.055 × 10⁻⁵ m

λ = 0.55 × 10⁻⁶ m

λ = 550 × 10⁻⁹ m

λ = 550 nm

So, the wavelength of the light is 550 nm

Learn more about double slit interference here:

https://brainly.com/question/4449144

which of the following is used to transport sound waves
A.medium
B.vacuum
C.mass
D.light​

Answers

I think the answer is d.right?

A mountain climber encounters a crevasse in an ice field. The opposite side of the crevasse is a height h lower, and is separated horizontally by a distance w. To cross the crevasse, the climber gets a running start and jumps in the horizontal direction. If the height of the crevasse increases but the width remains the same, then,

Select one:

O a. the minimum speed needed to cross the crevasse stays the same.

O b. the minimum speed needed to cross the crevasse will depend on the mass of the mountain climber.

O c. the minimum speed needed to cross the crevasse decreases.

O d. the minimum speed needed to cross the crevasse increases.

O e. the minimum speed needed to cross the crevasse will depend on the weight of the mountain climber.​

Answers

Jdjdjdhdhdjdhhdhdjdjdjd

5. A quarterback throws the football to a stationary receiver who is 31.5 m
down the field. If the football is thrown at an initial angle of 40.0° to the
ground, at what initial speed must the quarterback throw the ball for it
to reach the receiver? What is the ball's highest point during its flight?

Answers

The projectile launch equations allow to find the results for the questions about the movement of the ball are:

The initial velocity is:   v₀ = 17.7 m / s. The maximum height is:   y = 16 m.

Given parameters

Horizontal distance x = 31.5 m Launch angle tea = 40º

To find

The initial speed. Maximum height.

Projectile launching is an application of kinematics, where on the x-axis there is no acceleration and on the y-axis is the gravity acceleration.

The range is the distance traveled for the same departure height, see attached.

.

          R =[tex]\frac{v_o^2 \ sin 2\theta}{g}[/tex]  

         [tex]v_o^2 = \frac{ g R}{sin 2 \theta }[/tex]  

Let's calculate.

          v₀² = [tex]\frac{9.8 \ 31.5}{sin \ (2 \ 40)}[/tex]9.8 31.5 / sin (2 40.0)

          [tex]v_o = \sqrt{313.46}[/tex]o = ra 313.46

          v₀ = 17.7 m / s

At the point of maximum height the vertical speed is zero.

          v² = v₀² - 2 g y

          0 = v₀² - 2g y

          y = [tex]\frac{v_o^2}{2g}[/tex]  

Let's calculate.

         y = [tex]\frac{17.7^2}{2 \ 9.8}[/tex]  

         y = 16 m

In conclusion, using the projectile launch equations we can find the results for the questions about the movement of the ball are:

The initial velocity is: v₀ = 17.7 m / s The maximum height is:  y = 16 m.

Learn more here:  brainly.com/question/10903823

I need the answer for this question

Answers

Answer:

Since impedance = omega * L we can use the equation for resistance:

20 + 12 + 10 in parallel with 7 we have

J1 = 42 * 7 / 49 = 6 H for the combination on the right

4 H + 6 H + 8 H = 18 H for the entire combination

What does it mean that " memory is organized in semantic
networks

Answers

Answer:

Semantic memory is a category of long-term memory that involves the recollection of ideas, concepts and facts commonly regarded as general knowledge. Examples of semantic memory include factual information such as grammar and algebra.

the height of the upper falls at Yellowstone falls is 33.2m. when the water reaches the botton of the falls, its speed is 25.8 m/s. neglecting air resistance, what is the speed of the water at the to of te falls.

Answers

Answer:

Hi there

The water acquires a vertical velocity component during the fall equal to

Vy = sqrt(2gH) = 25.5 m/s. Its velocity at the bottom is 25.8 m/s, so the horizontal component at the bottom must be sqrt[(25.8)^2 - (25.5)^2] = 3.9 m/s

That must be the horizontal component at the top also, since it does not change during the fall. It is the velocity magnitude there.

Brainliest pls

The use of non-renewable energy resources in the UK has changed in the last 30 years.
Explain how the use of energy resources has changed in the last 30 years.

Answers

Answer: Varies

Explanation: It became more relied upon, technology is responsible for this.

Change 1m2 in to cm2, mm2 and km2​

Answers

Answer:

1m² = 10000cm²

1m² = 1000000mm²

1m² = 1 × 10^-6

Explanation:

When coverting from square meter to square centimetre, multiply the area value by 10.

When coverting from square meter to millimetre, multiply the area value by 10⁶ ( 1 million )

When converting from meter square to kilometre square, divide the area value by 10^-6 ( 0.000001)

Does the stone remain at a constant speed? Or does it speed up?

Answers

Answer:

it would remain the same speed

Explanation: the rock isnt going down a hill or anything so therefore if gravity isnt pulling it down a slope then it would remain the same pace

Which statement about RNA polymerase is NOT true?

RNA polymerase reads a template strand of DNA 5' to 3'

RNA polymerase binds to a promoter region to initiate transcription

RNA polymerase adds a ribonucleotide to the 3' end of a growing RNA molecule

During transcription of a gene, RNA polymerase reads only one strand of DNA

Please explain!

Answers

Answer:

RNA polymerase reads a template strand of DNA 5' to 3'

Explanation:

RNA polymerase is the enzyme accountable for the transcription of the DNA. It shows one coast of the DNA and transcribed within the RNA. It combines the nucleotide to the 3' conclusion of the expanding series of the RNA. It commences the method by connecting to the promoter area of the gene. The enzyme increases nucleotide, not ribonucleotide.

Therefore, A. RNA polymerase reads a template strand of DNA 5' to 3' is false.

Answer:

RNA polymerase reads a template strand of DNA 5' to 3'.

Explanation:

RNA synthesis is less processive during elongation than during initiation. Synthesis begins with the polymerase binding two rNTP molecules. The polymerase frequently releases the nascent transcript before it reaches 8-10 nucleotides in length.

Am object of mass in a circular path of radius 100metres with the speed of 10metres/second.calculate the acceleration towards the center​

Answers

Answer:

is 6

Explanation:

h

Explain how friction keeps a nail in place in a block of wood. If you try pull out the nail which way does friction act? I will give brainliest!

Answers

Answer:

Friction acts in the opposite direction of the velocity. As static friction acts in the opposite direction to the acceleration. (opposite way)

Explanation:

b) A ball thrown vertically into the air
Discuss newton law

Answers

The first law is used to visualize this. The ball is at a consistent velocity, unless acted on by another force, when the ball goes upwards and there's no force acting on it, it keeps going upwards, but there is gravity. When the ball is going up, you do not interact with it, thus only gravity is the only force, making the ball go downwards.

To examine this, apply the first law. When the ball is moving upward and there is no force acting on it, it continues to move higher but there is gravity. The ball is at a constant velocity unless pushed upon by another force.

What is gravity?

According to Newton's law of gravity, every particle of matter in the universe is attracted to every other particle with a force that varies directly as the product of their masses and inversely as their distance from one another.

Anything that can alter an object's motion is a force. When you toss a ball, you apply force in a direction that determines the direction in which it will move. The ball travels farther the harder you toss it because it is under greater stress.

The ball continues to go upward even though there is no force pushing against it because of gravity. Unless another force pushes on it, the ball is moving at a steady speed.

Thus, this way, when ball thrown vertically into the air shows Newton's first law.

For more details regarding Newton's laws of motion, visit:

https://brainly.com/question/29775827

#SPJ2

Please help if u can thanksss

Answers

Answer:

yes its okay i think so it is the correct answer

what a function of vacuole

Answers

Answer:

A vacuole is in both, plant and animal cells. It's main purpose is to isolate waste products, or in other words making sure that harmful materials won't damage the cell.

Answer:

In animal cells, they help sequester waste. In plants, they help maintain water balance.

Other Questions
13 = 1/6y +2x plz help What value of x satisfies the equation 1/2 x-5(x-1/3)=5/4 x+3 on 13, 1.7.21Points: 0 of 1SaveA bank loaned out $18,000, part of it at the rate of 7% per year and the rest at 15% per year. If the interest received in one year totaled $2000, how much was loanedat 7%?How Which process occurs during the light-dependent reactions in photosynthesis? what is 159 divided by 3? Which function has two distinct real zeros?A.) F(x)=2x+2B.) F(x)=(x-2)C.) F(x)=x+2D.) F(x)=lxl-2 What equation is graphed in this figure?A: y3=32(x+1)B: y+1=23(x3)C: y4=23(x+2)D: y+2=32(x2) The Mediterranean island, Cyprus, was formed at what plate boundary?A) convergentB) divergentC) transformplsss help me What factors led the United States into the Spanish American war. A. cuban war for independence- Cubans wanted the U.S to get involved to help fight the Spanish. B. Yellow Journalism- Newspapers were swaying the U.S public against the Spanish. C. Explosion of the USS Maine- Ship exploded the American Press and government blamed SpainD. All the above 3. Consider the iterative rules you wrote in Problem 2. (a) Explain why the rules are functions. (b) Your friend says that because the rules are functions, they can be graphed and must have y-intercepts. How would you respond to your friends comment? (c) Your friend uses your rules to determine the outputs when the inputs are 18.5. Explain why her outputs are meaningless in this situation. What would you tell her about the inputs she can use? Answer: Based on your experimental results, categorize each microbe as preferring isotonic environments, being halotolerant, or as a halophile. which activities of the body are controlled by the autonomic nervous system? 23/24 as a decimal rounded to the nearest hundredth In the field of organizational behavior, organizations are described as Poppy gives one half of a cake to her big brother and the other half to her three friends who share it equally. What fraction of the cake does each friend get? Please help!! Hhhhheeeeelllpppp????? I am excited to answer the test explain what led to the collapse of the democratic-republican party Which example shows an endothermic reaction?reactants + thermal energy --> productsproducts + thermal energy --> reactantsproducts --> reactants + thermal energyreactants --> products + thermal energyplease help 15. Brown eyes (B) are dominant over blue eyes (b).Using this example, explain how a child can have atrait that neither parent expresses physically. Use aPunnett Square to validate your answer.