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
Answer:
The angle is 18.3 degree.
Explanation:
A uniformly charged infinite plane, density σ = 4 x 10^-9 C/cm^2, 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. When in equilibrium, by what angle is the string hanging the ball to the plane?
surface charge density, σ = 4 x 10^-5 C/m^2
Charge, q = 10^-8 C
mass, m = 0.008 kg
Let the angle is A and the tension in the string is T.
The electric field due to a plane is
[tex]E =\frac{\varepsilon \sigma }{2\varepsilon o}\\\\E =\frac{4\times 10^{-5}}{2\times 8.85\times 10^{-12}}\\\\E = 2.26\times 10^6 V/m \\[/tex]
Now equate the forces,
[tex]T sin A = q E.... (1)\\\\T cos A = m g ..... (2)\\\\divide (1) by (2)\\\\tan A = \frac{10^{-8}\times 2.6\times 10^6}{0.008\times 9.8}\\\\tan A = 0.33\\\\ A = 18.3 degree[/tex]
An object is moving with an initial velocity of 9 m/s. It accelerates at a rate of 1.5 m/s2
over a time of 20 s. What is its new velocity?
Answer:
39 m/s²
Explanation:
initial Velocity (u) = 9m/s
acceleration (a) = 1.5m/s²
time(t) = 20s
V=u + at
V=9 + 1.5(20)
V=9 + 30
V=39m/s
What is the name of the part of the wave that is labeled -
answer: amplitude
the ones who have to watch the video
Answer:
amplitude
Explanation:
sound travel and it amplifies
difine scalar quantity
Scalar quantity are physical quantities that have just magnitude, not direction.
It is always positive.Examples: Speed, distancethe weight of body is less at moon than its weight is more at earth
Answer:
Gravity
Explanation:
There's no gravity on space so you're floating
please help with a step by step method
Answer:
Explanation:
This is a First Law of thermodynamics problem. We have to remember that the total energy available to a system is constant throughout the whole problem and that energy cannot be created or destroyed. So we need to find the total energy available right at the start. Well it just so happens that we are told that the total energy is 1000J and that it is all potential energy when the sphere is at rest and is 25 m off the ground. If the object isn't moving, all the energy is potential until it starts moving and the energy begins to convert from potential to kinetic a little bit at a time. The thing that we don't know is the mass of the shpere. Begin with the fact that the PE = 1000 (I'm going to se 2 sig fig's since there's only 1 in 1000). If
PE = 1000 and PE = mgh, then
1000 = m(9.8)(25) so
m = 4.1 kg
We also need the height at which this sphere has a PE of 600. Again, if
PE = 600 and PE = mgh, then
600 = (4.1)(9.8)h so
h = 15 Filling in the total energy equation now, using the fact that the total energy available to the system is 1000J:
TE = PE + KE and
1000 = (4.1)(9.8)(15) + [tex]\frac{1}{2}(4.1)v^2[/tex] and we are looking for v.
1000 = 6.0 × 10² + 2.1v² so
[tex]v=\sqrt{\frac{1000-6.0*10^2}{2.1} }[/tex] and
[tex]v=\sqrt{\frac{4.0*10^2}{2.1} }[/tex] gives us
v = 14 m/s
What is the correct equation for the y axis of object B?
Answer:
[tex]N_B-W_B = 0[/tex]
Explanation:
There are two forces acting on object B. If we consider the law of equilibrium, then the two forces must be equal in magnitude, for the object to remain in equilibrium position:
[tex]N_B = W_B\\\\N_B-W_B = 0[/tex]
Therefore, the correct answer of the given question, from the given choices, is:
[tex]N_B-W_B = 0[/tex]
If a car is moving on a straight line with a velocity of 40 m/s and it changes its velocity to 60 m/s in 4 seconds, calculate its acceleration.
Answer:
5m/s²
Explanation:
Initial Velocity= 40m/s
Final Velocity=60m/s
Time = 4s
a=(v-u)/t
a=60-40/4
a=20/4
a=5m/s²
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A circular loop of radius 0.0400 m is
oriented 35.0 degrees to a 0.152 T
magnetic field. What is the magnetic
flux through the loop?
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Hint: How do you find the area of a circle?
[?] x 10"") Wb
Pls I need helpppp!
Answer:6.26*10^-4
Explanation:
The magnetic flux through the loop is 6.255 x 10⁻⁴ Weber.
What is magnetic flux?The number of magnetic field lines passing through a cross-section area defines the magnetic flux. It is denoted by ∅.
∅ = BAcosθ
Given is the magnetic field B = 0.152T, radius r = 0.04m and the angle of orientation θ=35.0 degrees
Area of cross- section A = πr² = 3.14 x ( 0.04)² = 5.024 x 10⁻³ m²
Magnetic flux, ∅ = 0.152 x 5.024 x 10⁻³ x cos 35°
∅ = 6.255 x 10⁻⁴ Weber
Thus, the magnetic flux through the loop is 6.255 x 10⁻⁴ Weber.
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How did the English bill of rights impact the colonists views of government?
The English Bill of Rights helped to shape the colonists' views of government by promoting the ideas of individual liberty, representative democracy, and limited government.
What is English bill of rights?The English Bill of Rights is a document that was passed by the Parliament of England in 1689. It was a key moment in the development of modern democratic government, as it established certain rights and protections for English citizens, such as the right to bear arms, the right to a fair trial, and the prohibition of cruel and unusual punishment.
The English Bill of Rights also limited the power of the monarchy, requiring the king or queen to obtain the consent of Parliament before levying taxes or making other important decisions. Its influence can still be seen today in many democracies around the world.
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define acceleration what it's formula
Answer:
The definition of acceleration is a change in the rate of motion, speed or action.
hope it helps.stay safe healthy and happy..Acceleration is the rate of change of velocity.
[tex]acceleration = \frac{(final \: velocity - initial \: velocity)}{time} \\ or \\ a = \frac{(v - u)}{t} \\ \\ The \: S.I. \: unit \: of \: acceleration \: is \: \frac{m}{ {s}^{2} } \: or \: m {s}^{ - 2} [/tex].
My last year's notes on acceleration is attached. Hope it helps you!!
What is the colour of a shirt which has blue and white stripes when put under yellow light? Explain.
Answer:
Black and yellow strips.
Explanation:
Color of shirt is blue and white stripes
When the shirt is seen in the yellow light, the blue color do not reflect any color so it appears black and the white color reflects the yellow light so it appears yellow.
Thus, the color of shirt is blue appears black and white appears yellow.
why is the tin of regular coke sink in water?
Answer:
This happens because the tin is made of estañum, and the estañum is denser than the water.
Remember the relation:
density = mass/volume
The general rule is that if an object is denser than water, it will sink
If an object is less dense than water, like a piece of wood, it will float.
And if an object has the same (or nearly the same) density as water, it will float, but fully submerged.
Based on that, we can conclude that the tin will sink because it's density is larger than the density of the water.
A box of tools rests in the back of a pickup truck. The truck accelerates to the north and the box remains at rest in the truck. The direction of the friction force on the box of tools is _____.
Answer:
The direction of friction force is toards north.
Explanation:
A tool box is at rest on the back of a track. The truck is accelerating towards north.
As the frame of reference is acceleratinf so it is a non inertial frame of reference.
Thus, teh toolkit experineces a pseudo force towards the south direction.
According to the question, the toolbox is at rest so the fiction force is balances by teh psheudoforce, and thus teh friction force is acting toards north.
A student is investigating the affect of different salts on melting points. Four patches of ice of equal
size are roped off and a
different type of salt is poured on each, one receives table salt (NaCl), one
receives Calcium Chloride (CaCl2), one receives Potassium Carbonate (KCO3) and the fourth
receives inert sand instead. Each patch receivęs an equal amount of salt or sand. The student
measures the volume of ice remaining and subtracts it from the original volume of ice to see how
much melted away. What is a control variable in this experiment?
A. The size of the ice patches.
B. The type of salt applied to the ice.
C. The amount of ice that melted.
D. None of these.
Answer:
A. The size of the ice patches
Explanation:
In an experiment, the control variable also known as the CONSTANT is the variable that must be kept uniform or the same for all groups throughout the experiment in order not to influence the outcome of the experiment.
According to the experiment described in this question, the effect of different salts on melting points is investigated by a student. Sodium chloride (NaCl), Calcium Chloride (CaCl2), Potassium Carbonate (KCO3) and inert sand are the four types of salt used. The volume of the ice used and melted was finally measured. This means that the SIZE OF THE ICE PATCHES USED is the control variable of the experiment as the same size was used for all groups throughout.
Answer:
the size of the ice patches
Explanation:
a ball is thrown straight up into the air while the ball is traveleling upwards what are the magnitue and direction
Answer: hi your question is incomplete attached below is the complete question
answer :
magnitude of acceleration : | a | = g = 9.81 m/s^2
direction : a = - g j
Explanation:
Neglecting Air resistance
magnitude of acceleration :
| a | = g = 9.81 m/s^2
Direction of acceleration
a = - g j ( given that the direction of acceleration is against the acceleration due to gravity i.e. in the opposite direction )
Please help
Will give the brainliest!
c. aluminium
d. it cannot travel through glass
e. mass of 55kg, takes 25s to gain a height of 15m
Find the time taken if the speed of a train increased rom 72km/h to 90km/h for 234km
Answer:
2.89 hours
Explanation:
given :
Vo = 72 km/h
Vt = 90 km/h
S = 234 km
find : the time taken (t) = ?
solution :
2.a.s = Vt² - Vo²
2.a.(234) = 90²- 72²
468.a = 8100 - 5184
= 2916
a = 2916/468 = 6.23 km/h²
so,
t = (Vt-Vo) /a
= (90-72)/ 6.23
= 18/ 6.23
= 2.89 hours
Suppose that you are standing on a train accelerating at 0.20g (where g is the acceleration due to gravity). What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide
Answer:
0.2
Explanation:
The given parameters are;
The acceleration of the train, a = 0.2·g
The mass of the person standing on the train = m
Let μ represent the coefficient of static friction, we have;
The force acting on the person, F = m × a = m × 0.2·g
The force of friction acting between the feet and the floor, [tex]F_f[/tex] = m·g·μ
For the person not to slide we have;
The force acting on the person = The force of friction acting between the feet and the floor
F = [tex]F_f[/tex]
∴ m × 0.2·g = m·g·μ
From which we get;
0.2 = μ
The coefficient of static friction that must exist between the feet and the floor if the person is not to slide, μ = 0.2.
please help me with my question due tomorrow morning,
Answer:
D)7 1/2 or 15/2
Explanation:
Let's calculate Combined resistance of the parallel first
1/Rt= 1/2+1/6=4/6
Rt=6/4 which is also equal with 3/2
Now let's add it with the series one
Rt= 6+3/2
=15/2 And when we put that un a mixed fraction 7 1/2
A car going around a curve with a radius of 15m experiences a centripetal acceleration of 2.5 m/s2. How fast is the car going?
0.17m/a
38 m/s
6.1 m/s
6.0 m/s
Answer:
Explanation:
The formula for centripetal acceleration is
[tex]a_c=\frac{v^2}{r}[/tex] . Filling in:
[tex]2.5=\frac{v^2}{15}[/tex] and
[tex]v=\sqrt{2.5(15)}[/tex] so
v = 6.1 m/s
In a whispering gallery, a person standing at one focus of the ellipse can whisper and be heard by another person standing at the other focus, because all sound waves that reach the ceiling from one focus are reflected to the other focus. A hall 120 feet in length is to be designed as a whispering gallery. Of foci are located 40 feet from the center, how high will the ceiling be at the center
Answer:
Hence, the height of the ceiling at the center is 44.72 feet.
Explanation:
Consider that a whispering gallery has a length of 120 feet, and the foci are located 40 feet from the center.
Assume that the shape is a horizontal semi-ellipse with a center (0,0) and has the equation,
[tex]\frac{x^{2} }{ a^{2} } + \frac{y^{2} }{b^{2} } =1[/tex] where a>b,
so,
2a = 120
a = 60
and
c = 40
Therefore, the equation of the ellipse is,
[tex]c^{2} = a^{2} -b^{2} \\\\40^{2} = 60^{2} -b^{2}\\\\b^{2} =2000\\\\b= 44.72.[/tex]
Match the synthetic materials with the processes used to make them.
If a rock has a speed of 12 m/s as it hits the ground, from what height did it
fall, assuming its initial speed was zero? Its mass is 50 kg.
A. 600 m
B. 4.2 m
C. 12 m
D. 7.3 m
Answer:
To find the height the following formula should be used:
v 2 = u 2 + 2aH
Explanation:
Assuming this occurs on earth, a= 9.8 ms -2
-2 2
12=0+2 x9.8 x H
144
_______ =H
2 x 9.8
H= 7.35m
The spin of Earth creates the Coriolis effect. This effect causes which current patterns to occur? Choose all that apply
Surface ocean water in the Northern Hemisphere moves clockwise.
Surface ocean water in the Southern Hemisphere moves clockwise.
Surface ocean water in the Northern Hemisphere moves counterclockwise.
Surface ocean water in the Southern Hemisphere moves counterclockwise.
Surface ocean water moves clockwise in both hemispheres.
Surface ocean water moves counterclockwise in both hemispheres.
Answer:
The correct answer is options (1) and (4).
Explanation:
Due to the rotation of the earth Coriolis force is generated. As the earth rotates from the west to the east, it changes the pattern of global wind and ocean water movement.
This force allows the ocean surface water to move in the clockwise direction in the northern hemisphere, and anticlockwise in the southern hemisphere.
Thus, the correct answer is options (1) and (4).
[tex]explain \: \\ \\ how \: rainbow \: form \: {?}[/tex]
. A car accelerates uniformly from 0 to 72 km/h in 11.5 seconds.
a) What is the acceleration of the car in m/s2? b) What is the position of the car by the time it reaches the velocity of 72 km/h?
Answer:
Explanation:
First job is to convert 72 km/hr to m/s:
[tex]72\frac{km}{hr}[/tex] × [tex]\frac{1000m}{1km}[/tex] × [tex]\frac{1hr}{3600s}[/tex] = 2.0 × 10¹ m/s
Now to find the acceleration which is
[tex]a=\frac{v_f-v_0}{t}[/tex] and filling in:
[tex]a=\frac{2.0*10^1-0}{11.5}=1.7\frac{m}{s^2}[/tex] That's part a. Part b want to know how far the car can get in 11.5 seconds (because that's the time it takes for the car to get to 72 km/hr). Since we know that the car can get 2.0 × 10¹ meters in 1 second, that means that in 11.5 seconds, the car can get 11.5(2.0 × 10¹) which is 230 meters.
A toy rabbit of mass 0.15 kg is accelerated at 8 m/s2 by an angry toddler. Calculate the force exerted on the toy rabbit.
Answer:
1.2 N
Explanation:
Given that,
Mass (m) = 0.15 kgAcceleration (a) = 8 m/s²We are asked to calculate force exerted (F).
[tex]\longrightarrow[/tex] F = ma
[tex]\longrightarrow[/tex] F = (0.15 × 8) N
[tex]\longrightarrow[/tex] F = 1.2 N
Define equilibrium and explain first condition of equilibrium. Pease make it fast...
Answer:
First Condition of Equilibrium
For an object to be in equilibrium, it must be experiencing no acceleration. This means that both the net force and the net torque on the object must be zero. Here we will discuss the first condition, that of zero net force. ... Fnet=0 F net = 0.
. What is a normal force? It acts against an object slowing it down. It acts perpendicular to an object. It acts with an object adding to its speed. It acts parallel to an object.
Answer:
Explanation:
This is basically asking you what the definition of Normal force is. Normal force is the force that pushes back against the weight of something that is sitting (or standing or lying) perpendicular to it. That's why, when you stand on a floor you don't crash through the floor OR go shooting up into space. The Normal force is equal but opposite to your weight. The floor exerts the normal force (pushing up and is positive) while your weight is opposing it (pushing down and is negative.) Perpendicular is the key word here, I believe.
A normal force acts perpendicular to an object. It is the force exerted by a surface to support the weight of an object resting on it.
The normal force acting against an object slowing it down or acting with an object adding to its speed, are not accurate descriptions of the normal force. The normal force primarily deals with the support of an object on a surface and is directed perpendicular to that surface.
Normal force is the force that pushes back against the weight of something that is sitting (or standing or lying) perpendicular to it. That's why, when you stand on a floor you don't crash through the floor OR go shooting up into space. The Normal force is equal but opposite to your weight. The floor exerts the normal force (pushing up and is positive) while your weight is opposing it (pushing down and is negative.)
Therefore, A normal force acts perpendicular to an object. It is the force exerted by a surface to support the weight of an object resting on it.
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