: Một mặt phẳng vô hạn tích điện đều, mật độ σ = 4.10-9 C/cm2, đặt thẳng đứng trong không khí. Một quả cầu nhỏ có khối lượng 8 g, mang điện tích q = 10-8 C treo gần vào mặt phẳng, sao cho dây treo lúc đầu song song với mặt phẳng. Lấy g = 9,8m/s2. Khi cân bằng, dây treo quả cầu hợp với mặt phẳng 1 góc bằng bao nhiêu?

Answers

Answer 1

Answer:

The angle is 16 degree.

Explanation:

A uniformly charged infinite plane, density σ = 4.10-9 C/cm2, is placed vertically in air. A small ball of mass 8 g, with charge q = 10-8 C, hangs close to the plane, so that the string is initially parallel to the plane. Take g = 9.8m/s2 . In equilibrium, by what angle does the string hanging from the ball make an angle with the plane?

Surface charge density,   σ = 4 x 10^-9 C/m^2

charge, q = 10^-8 C

mass, m = 0.008 kg

Let the tension is the string is T and the angle is A.

[tex]T sin A = q E....(1)\\\\T cos A = m g .... (2)\\\\Divie (1) by (2)\\\\tan A =\frac{q E}{m g}\\\\tan A = \frac{10^{-8}\times 4\times 10^{-5}}{2\times 8.85\times 10^{-12}\times 0.008\times9.8}\\\\tan A = 0.288\\\\A = 16 degree[/tex]


Related Questions

A boy shoves his stuffed toy zebra down a frictionless chute. It starts at a height of 1.45 m above the bottom of the chute with an initial speed of 1.23 m/s . The toy animal emerges horizontally from the bottom of the chute and continues sliding along a horizontal surface with a coefficient of kinetic friction of 0.231 . How far from the bottom of the chute does the toy zebra come to rest? Assume g=9.81 m/s2 .

Answers

Answer:

The answer is "4.97 m".

Explanation:

[tex]u = 1.23\ \frac{m}{s}\\\\[/tex]

[tex]H= 1.45 \ m\\\\[/tex]

[tex]\mu = 0.231\\\\[/tex]

The law of conservation tells us that heat energy at the top with kinetic energy at the top equals kinetic energy at the base.

[tex]mgh+\frac{1}{2}mu^2=\frac{1}{2}mv^2\\\\2gh +u^2 =v^2\\\\v=\sqrt{u^2+2gh}[/tex]

[tex]v=\sqrt{(1.23\ \frac{m}{s})^2+2(9.81 \frac{m}{s^2}) +(1.45\ m)[/tex]

   [tex]=\sqrt{1.5129+19.62 +1.45}\\\\=\sqrt{22.5829}\\\\=4.75\ \frac{m}{s}[/tex]

Friction force is given by the formula

[tex]f=-\mu mg \\\\ma= -\mu mg\\\\a=-\mu g\\\\[/tex]

[tex]= -(0.231) \ (9.81\ \frac{m}{s^2})\\\\=-2.26611 \ \frac{m}{s^2}[/tex]

Now by using an equation of motion as

[tex]v^2-u^2= 2as[/tex]

From the above the distance traveled is

[tex]S=\frac{v^2-u^2}{2a}[/tex]

[tex]S=\frac{(0)^2-(4.75\ \frac{m}{s})^2}{2(-2.26611\ \frac{m}{s^2})}\\\\[/tex]

   [tex]=\frac{-(4.75\ \frac{m}{s})^2}{2(-2.26611\ \frac{m}{s^2})}\\\\=\frac{-22.5625}{-4.53222}\\\\=4.97[/tex]

In other words, the distance from the bottom of the chute to the point where the toy zebra comes to rest is [tex]s = 4.97\ m[/tex]


What kind of circuit is the one shown below?
A. Series
B. Parallel
C. Open
D. Combination

Answers

That's a parallel circuit. (B)

When current from Point-A reaches the 3-way intersection just to the right of Point-B, it has to make a choice:  Either turn left, go through B, and light the lower bulb, or go straight and light the upper bulb.

A circuit that has any "decision" points in it is a parallel circuit.  What happens in the real world is:  The current splits up.  Some of the current that reaches the intersection turns left toward Point-B, and the rest of it goes straight up.

A series circuit is one in which there's only one possible path all the way around.  There are no intersections of more than 2 roads, and no electron ever has to decide which way to flow.

An open circuit is one in which there's a break somewhere along the line and electrons can't jump across it.  It's like a railroad where a big piece is cut out of the track somewhere.  So no trains can travel on that route, and there's no current flowing anywhere in the circuit.

I'm not so sure about a "combination" circuit.  I guess you could give that name to a complicated circuit that has some series parts and some parallel-parts.  Personally, I'd call that a "series-parallel" circuit.  But it really doesn't matter right now.  Whatever the word means, the circuit in the picture is definitely not a "combination" circuit.

Answer:

B. Parallel Circuits

Explanation:

A parallel circuit is constructed by connecting the terminals of all the individual load devices so that the same value of voltage appears across each component. In a parallel circuit, charge divides up into separate branches such that there can be more current in one branch than there is in another.

hope i helped

what type of simple machine is shown in the diagram?write the length and height of slope in it. Please help ASAP!!!​

Answers

the machine shown in the diagram is called a tramp.

the height of the tramp is 5 and the length is 12

Answer:

Incline plane

5/12 rise/run

Explanation:

Incline plane

5/12 rise/run

Saul is testing an installation and discovers a short circuit what’s causing this
A.high current

B.high voltage

C.low resistance

D.low voltage

Answers

Answer:
C. Low resistance

Answer:

im pretty sure that it's (A.) High current

Explanation:

pf

not 100% sure, tho

HELP ASAP!!!
What size object (impactor) may create such a crater?

Answers

Answer:

I HOPE IT WILL HELP YOU.

:D

What is not one of the main uses of springs?
A. Bike suspension
B. The seasons
C. Clock making
D. Car suspension

Quick answer

Answers

Answer:

b. the seasons

Explanation:

Explanation of the physics involved i the northern lights(aurora borealis) why can't it occur in mire southerns latitudes?

Answers

Answer:

The northern lights come from the interaction of electrically charged particles given off by the Sun surface during solar storms and the Earth's magnetic field which is pointed in the northern to southern poles of the Earth. Therefore, the charged particles that travel through millions of miles from the Sun to the Earth accelerate towards the magnetic poles and appear as the northern (and southern) lights

Boreal is an adjective word for the north or northern regions. In the southern latitudes, in the southern hemisphere, the phenomenon is called aurora australis (australis is the adjective for 'of the south')

Explanation:

A car generator turns at 400 rpm (revolutions per minute) when the engine is idling. It has a rectangular coil with 300 turns of dimensions 5.00 cm by 6.46 cm that rotates in an adjustable magnetic field. What is the field strength needed to produce a 24.0 V peak emf

Answers

Answer:

The field strength needed to produce a 24.0 V peak emf is 0.5913 T

Explanation:

From the formula for maximum emf of a generator,

[tex]emf_{max}= NAB\omega[/tex]

∴ [tex]B = \frac{emf_{max} }{NA\omega}[/tex]

Where N is the number of loops

A is cross section of loops

B is magnetic field strength

ω is the angular frequency of loops

From the question, [tex]emf_{max} = 24.0V[/tex]

N = 300 turns

A = l × b ( since it is a rectangular coil)

A = 6.46 cm × 5.00 cm

A = 0.0646 m × 0.05 m

A = 0.00323 m²

ω = 400 rpm = (400/60)×2π rad/s

ω = 41.8879 rad/s

Putting all the parameters into the formula

[tex]B = \frac{emf_{max} }{NA\omega}[/tex]

[tex]B = \frac{24.0}{300\times0.00323\times41.8879}[/tex]

[tex]B = 0.5913T[/tex]

Hence, the field strength needed to produce a 24.0 V peak emf is 0.5913 T

the speed of pendulum is slowest: a) at mountain b) at sea level​

Answers

Answer:

At sea level

Explanation:

Because there is higher air pressure

True or False. A compound is formed when two or more elements are combined to make a new substance with
its own properties


True
Fase

Answers

I believe that the answer is true

Hope this helps :))

PLS MARK AS BRAINLY PLSSSS

Which nucleus completes the following equation?
Please ignore the answer I chose, it might be wrong

Answers

Answer:

D. [tex]^{39}_{18} Ar[/tex]

Explanation:

The given nuclear equation is the beta decay of chorine in which an electron, known as a beta particle, is given off from within the nucleus due to the breakdown of a neutron within the nucleus into a proton and a beta particle, such that the atomic number is increased by 1 from 17 to 18, which is the atomic number or argon, Ar, as follows;

[tex]^{39}_{17}Cl \ \rightarrow \ ^0_{-1} e + \ ^{39}_{18} Ar[/tex]

Annie has a soccer ball and a cake ball she kicks each ball with the same Force the soccer ball accelerates at 3 m per second squared and the kickball accelerates at 5 m per second squared use Newton's law to describe why the kickball has a greater acceleration

Answers

Answer: The acceleration will be greater in the kickball than the soccer ball since the kick ball has a smaller mass and provided they are acted upon with equal force magnitude.

Explanation:

We can prove this by substituting with numerical values.

Say the force she kicked both balls with was 30 N. The mass of the soccer ball is 10kg and the mass of the kickball is 6kg.

Applying Newtons Second Law, F = ma

For the soccer ball:

30 = 10a
a = 30/10
a = 3

For the kickball:

30 = 6a
a = 30/6
a = 5

Hence the kickball will travel with a greater acceleration given the same force is acted upon and has a smaller mass than the soccer ball

Hope this helps, brainliest would be appreciated :)

5. True or False: A beginner should start with long workout sessions and work down to shorter ones.
True
False

Answers

Answer:

false...............

Answer:

False A beginners should start from shorter ones to long work sessions

Explanation:

Hope it helps

Mark me as Brainliest plz!!

:DD

ITSMISSBADGURLX

A force of 100 N stretches a spring by 5cm. Calculate the work done.

Answers

Answer:

Work done is 5 J

Explanation:

Workdone = Force × distance

[tex]{ \sf{W = 100 \times (5 \times {10}^{ - 2}) }} \\ { \sf{W = 5 \: joules}}[/tex]

Which type of wires (copper, aluminum, or string) are ferromagnetic metals?

Answers

Answer:

Copper isn't ferromagnetic,

Aluminum isn't ferromagnetic,

String has a ferromagnetic property

So in conclusion:

The answer is strings :)

The moving bicycle moves for sometime even after stopping the paddling.why​

Answers

Answer:

when you are paddling the push carry on when you paddle the hard put on the push.

Answer:

Because of inertia

Explanation:

As stated in Newton first law "An object at rest will stay at rest, an object in motion will stay in motion unless it is acted upon by a force."

For an example:

If you have a drink without a lid in a car and a car suddently the car stop, u will automatically try to catch the drink preventing it from spilling. This is because that the drink that was in motion with the car want to stay in motion, but when the car stop, the drink still wanna be in motion, that's why it will be flying off and spill if u don't catch it.

Back to the question:

if a bicyccle is in motion, it will wants to be in motion untill a force act upon it, let's say a bump or fricition.

hope this help. give me the brainliest if u can.

What is one Pascal pressure? What is its unit?​

Answers

Explanation:

the force acting perpendicularly on unit area of surface

unit=pascle .

A pressure of one Newton per square meter .. The SI unit of 1 Pascal pressure is 1 Newton per square metre .

Please help me , I also have to show work on paper

Answers

Answer:

Choose B

Explanation:

Hope Can I help you

can anyone help me with this one​

Answers

Answer:

c) sin c /sin d

because light is moving from denser to shallower medium

b) refraction of light

Explanation:

what is metel and non metel ?​

Answers

Answer:

Metals (like copper and aluminium) are good conductors of heat and electricity, while nonmetals (such as phosphorus and sulfur) are insulators.

Explanation:

i don't really have one i just know

Answer:

1 of them is metel and one is not

Explanation:

how is one standard kilogram defined in SI system?​

Answers

Answer:

One standard kilogram is define as the mass of platinium iridium cylinder having equal diameter and height kept at the particular condition of international bureo of weigh and measure sevre near paris.

the force between the earth and the body which is at a distance r from the center of the earth is F. What must be this distance for the force to be doubled.

Answers

Answer:

Explanation:

The gravitational force between the earth and another body is F = -GM_em/r^2 r where G = 6.67 times 10^-11 Nm^2/kg^2 is the gravitational constant, M_e = 5.97 times 10^24 kg is the mass of the earth, m is the mass of the other body, and r is the position vector of the second body with respect to the centre of the earth.

What is the difference between gross anatomy and microscopic anatomy?

Answers

There are two major types of anatomy. Gross (macroscopic) anatomy is the study of anatomical structures that can be seen by the eye, such as the external and internal bodily organs. Microscopic anatomy is the study of tiny anatomical structures such as tissues and cells.

Answer:

The gross (or macroscopic) anatomy: The study of anatomical features visible to the naked eye, such as internal organs and external features.

The microscopic anatomy: The study of minute anatomical structures on a microscopic scale, including cells (cytology) and tissues (histology).

V = ?
d= 15 m left
t = 5 s
What is the velocity?

Answers

Answer:

Velocity= 3[tex]ms^{-1}[/tex]

Explanation:

Formula to find velocity = Displacement/time taken

therefore, velocity= 15/5 ➤ Velocity = 3 [tex]ms^{-1}[/tex]

what are the factors of evaporation and give explanation​

Answers

Temperature and rate of evaporation are proportional to each other. Surface area: As the surface area increases, the rate of evaporation increases. The surface area and rate of evaporation are proportional to each other. Humidity: The rate of evaporation decreases with an increase in humidity.

Answer:

The three primaryfactors of evaporation are heat, atmospheric pressure (which determines the percentage of moisture) and the movementofair. At the molecular level, there is no strict boundary between the liquid state and the vapor state

A merry-go-round rotates with a centripetal acceleration of 18 m/s^2. If the outer horses are 9 m from the center of the ride. What is their velocity?
A. 12.7 m/s
B. 14.6 m/s
C. 16.3 m/s
D. 10.4 m/s

Answers

Answer:

A

Explanation:

a_c = v^2/r

v = sqrt*a_c × r*

v = sqrt * 18 × 9*

v = 9×sqrt *2*

v = 12. 7 m/s

Question 4: Scientists and engineers often plan investigations to see how changing one variable affects the outcome. A variable is any trait, condition or feature of something being tested. Imagine a team is testing the speed of a toy car. In trial 1, they test the car and measure how long it takes it to travel 2 meters. In trial 2, they want to investigate how changing a variable affects the car's speed. Which of the following plans is BEST for trial 2?

Answers

A variable, as its name implies, is something that can change, ideally, as the scientists and engineers want to.

Particularly we care for the independent variables, which are the ones we can control and affect the dependent variables, which are the outcomes we study.

For a quick example, think of an experiment where you heat something on an oven. The temperature of the oven can be set by the scientist, so the temperature is an independent variable because they can control it.

Now let's see the given experiment.

The team is testing the speed of the toy car.

remember that:

distance/time = speed.

We know that in the first trial, they test how long takes the car to travel 2 meters.

Now, what we can change for the second trial, knowing that the speed is the output that we are studying?

The answer is trivial, the only thing we can change in the given setup is the distance that the car travels, so in the next trial we should change the variable "distance travelled by the car" and see if it affects the output "speed of the car".

If you want to learn more about variables, you can read:

https://brainly.com/question/19585043

Which is the formula that describes the magnitude of an object's kinetic energy? A. kinetic energy = mass * (velocity)2 x 0.5
B. kinetic energy = mass x acceleration C. kinetic energy = mass x change in velocity
D. kinetic energy = mass x velocity​

Answers

Answer:

A

kinetic energy=(mv²)/2

(1/2)(mv²)

(mv²)*0.5

where m=mass and v=velocity/speed

What is the most accurate and precise method to measure the thickness of a coin? ​

Answers

Answer:

The most accurate and precise method to measure the thickness of a coin would be by a micrometer screw guage.

The most accurate and precise method to measure the thickness of a coin is with the help of a screw gauge.

What is a unit of measurement?

A unit of measurement is a specified magnitude of a quantity that is established and used as a standard for measuring other quantities of the same kind.

It is determined by convention or regulation.

Any additional quantity of that type can be stated as a multiple of the measurement unit.

The smallest length that a screw gauge can measure is called its least count.

Thus, if we have to measure the thickness of a coin using a screw gauge to measure a coin is the most exact and precise approach available.

Learn more about the unit of measurement here, refer to the link given below;

brainly.com/question/12629581

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Wagonium-292 has a half-life of 1 hour. If you started with an 80 gram sample, how much Wagonium-292 will remain after 4 hours? A.) 10g B.) 40g C.) 160g D.) 5G

Answers

After 1 hour, 80 g decays to 40 g.

After another hour (total 2 hours), 40 g decays to 20 g.

After another hour (total 3), 20 g decays to 10 g.

After one more hour (total 4), 10 g decays to (D) 5 g.

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