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]
Why does time have a direction? Please give your ideas I want to see them. Brainliest f0r most effort.:)
Answer:
it's a rule like water !!!!
Explanation:
Most importantly, time appears to run forward always never backwards. in other words there's perceived arrow of time and there's thermodynamic arrow of time, and they always point in a forward direction
for every system there are more states that seem chaotic then states that seem ordered.
the arrow of time seems to have something to do with that tendency. but to get from one instance to another where things get more entropy, we already need some kind of time, gotta admit that.
some (physicists) believe that time is an illusion, that the whole universe is already set in stone, like a block (the idea is therefore called block universe). from the perspective of a godlike outside observer the universe would be like a book, or a 4D movie. the characters might feel a movement of things in a direction, but rewinding it wouldn't feel different in any instance because the order in wich things happen is already written.
a different idea is that there are infinite many different futures and the further they are away, the less we can know for sure about them in a physical way. and this might also be work for the past, so that different parts could lead to one present.
when macroscopic information is deleted, it might not be reversible, so the past gets ultimately blurry. one example for deletion of macroscopic information this is the Library of Alexandria wich burned down.
all the quantum information is still conserved, but the order of things (like letters on pages) is lost and could have been in different configurations before. we can't ultimately not even see the past, as much as we would try.
personally the idea that the past is written in stone but the future is in flux doesn't make any sense for me. because than I could have free will now, but not from the perspective 10 days later.
the present would be a very special thing than, the stage where the universe likes to play.
maybe we can get a grasp on time if we look at it like rules for a game, like a cardboard game.
To get from one configuration to the next ,we must follow rules. like throwing dice and moving in monopoly.
gravity would be a simple real world example for such a rule, a natural law.
But no one would have a firm clue where this rules came from.
TLDR: I don't know and neither does anyone else for sure, not even top notch scientists.
the hardest questions are easy to formulate, but maybe even impossible for us to answer in a satisfying way. I hope we will understand those hard questions better one day, and maybe even get answers.
No me sale este problema :c, plano inclinado
Answer:
i didn't understand,
Explanation:
sorry
6. traction a. friction between a tire and the road.b. pushes a moving object out of a curve and into a straight linec. the ability of a car to hold a straight lined. a road higher in the center than on either edge 7. kinetic energy a.a force that keeps objects moving in a straightb. reduces the effects of inertiac. energy of motiond. a road higher in the center than on either edge 8. force of impact a. a force that keeps objects moving in a straight line.b. a road higher in the center than on either edgec. the force with which a moving vehicle hits another objectd. perception distance, reaction distance, and braking distance
Answer:
6. a. friction between a tire and the road
7. c. energy of motion
8. c. the force with which a moving vehicle hits another object
Explanation:
6. As a car moves along the road, the tires push back against the ground. As tires push back against the ground, the road exerts and opposing force to the motion of the tires. This opposing force is the friction between the tires and the road. This opposing force between the tires and the rad is called traction.
So, the answer is a
7. As an object moves, it has energy. This energy due to its motion is called kinetic energy.
So, the answer is c
8. When a moving vehicle hits another object, it exerts a force on the object. The process of the vehicle hitting the other object is called impact and the force exerted on the object is called the force of impact.
So, the answer is c.
A 5.0 kg block of ice is at rest at the top of a smooth inclined plane. The block is released and slides 2.0 m down the plane. Assuming there is no friction between the block and the surface, calculate
a) the gravitational potential energy at the top of the plane
b) the component of the weight parallel to the plane
c) the acceleration of the block
d) the velocity of the block at the bottom of the plane
e) the kinetic energy at the bottom of the plane.
Answer:
a) 98.1 Joules
b) 49.05 N × sin(θ)
c) 9.81 × sin(θ)
d) The velocity of the block at the bottom of the plane, v is approximately 6.264 m/s
e) 98.1 Joules
Explanation:
The given parameters of the block are;
The mass of the block, m = 5.0 kg
The distance down the plane the block slides, h = 2.0 m
The friction between the block and the surface = 0
Let θ represent the angle of inclination oof the plane
a) The gravitational potential energy, P.E. = m·g·h
Where;
g = The acceleration due to gravity ≈ 9.81 m/s²
∴ P.E. ≈ 5.0 kg × 9.81 m/s² × 2.0 m = 98.1 Joules
The gravitational potential energy, P.E. ≈ 98.1 Joules
b) The component of the weight of the block parallel to the plane, [tex]w_{\parallel}[/tex], is given as follows;
[tex]w_{\parallel}[/tex] = w × sin(θ) = m·g·sin(θ)
∴ [tex]w_{\parallel}[/tex] ≈ 5.0 kg × 9.81 m/s² × sin(θ) = 49.05 × sin(θ) N
The component of the weight of the block parallel to the plane, [tex]w_{\parallel}[/tex] ≈ 49.05 N × sin(θ)
c) The component of the weight along the inclined plane = The force with which the block moves along the inclined plane, therefore;
[tex]w_{\parallel}[/tex] = m·g·sin(θ) = m·a
Where a represents the acceleration of the block along the plane
Therefore, by comparison, we have;
g·sin(θ) = a
∴ a ≈ 9.81 × sin(θ)
d) Given that the motion of the block is 2.0 m downwards, we have;
The velocity of the block at the bottom of the plane, v² = 2·g·h
Therefore, v² ≈ 2 × 9.81 m/s²× 2.0 m = 39.24 m²/s²
v = √(39.24 m²/s²) ≈ 6.264 m/s
e) The kinetic energy at the bottom of the plane, K.E. = (1/2)·m·v²
∴ K.E. = (1/2) × 5.0 kg × 39.24 m²/s² = 98.1 J
In 'coin on card' experiment a smooth card is used.
Answer:
In coin card experiment smooth card is used so that the card can slide easily from glass
An object 2cm high is placed 3cm in front of a concave lens of focal length 2cm, find the magnification?
Answer:
0.4
Explanation:
A concave lens is a diverging lens, so it will always have a negative focal length. Image distance is always negative for a concave lens because it forms virtual images.
From the lens formula;
1/f = 1/u+ 1/v
- 1/2 = 1/3 - 1/v
1/v = 1/3 + 1/2
v= 6/5
v= 1.2 cm
Magnification = image distance/object distance
Magnification = 1.2cm/3cm
Magnification = 0.4
Mary drives at a speed of 35 mph (mile/hour). How long does it take for her to drive 98 miles?
__ hours
Answer:
2.8 hours
Explanation:
98 ÷ 35 = 2.8
A boy travels 12km east wards to a point B and then 5km southwards to another point C. Calculate the difference between the magnitude of the displacement of the boy and the distance travelled by him
The difference b/w the displacement and total distance traveled is 4km.
Explanation.
▪ total distance - displacement
= 17 km - 13 km
= 4 km...answer
How much energy has 4×10^10m^3 of water collected in a reservoir at a hight of 100 m from the power house ?What kind of energy is that?
Answer:
PE = 3.92x10^16J
potential energy
Explanation:
PE = m*g*h
mass of water = 1000kg/m³
(4*10^10m³)*1000kg = 4*10^13kg
PE = (4*10^13kg)*(9.81m/s²)*(100m)
PE = 3.92x10^16J
In a science museum, a 130 kg brass pendulum bob swings at the end of a 14.4 m -long wire. The pendulum is started at exactly 8:00 a.m. every morning by pulling it 1.7 m to the side and releasing it. Because of its compact shape and smooth surface, the pendulum's damping constant is only 0.010kg/s. You may want to review (Pages 405 - 407) . Part A At exactly 12:00 noon, how many oscillations will the pendulum have completed
Answer:
The time in which the pendulum does a complete revolution is called the period of the pendulum.
Remember that the period of a pendulum is written as:
T = 2*pi*√(L/g)
where:
L = length of the pendulum
pi = 3.14
g = 9.8 m/s^2
Here we know that L = 14.4m
Then the period of the pendulum will be:
T = 2*3.14*√(14.4m/9.8m/s^2) = 7.61s
So one complete oscillation takes 7.61 seconds.
We know that the pendulum starts moving at 8:00 am
We want to know 12:00 noon, which is four hours after the pendulum starts moving.
So, we want to know how many complete oscillations happen in a timelapse of 4 hours.
Each oscillation takes 7.61 seconds.
The total number of oscillations will be the quotient between the total time (4 hours) and the period.
First we need to write both of these in the same units, we know that 1 hour = 3600 seconds
then:
4 hours = 4*(3600 seconds) = 14,400 s
The total number of oscillations in that time frame is:
N = 14,400s/7.61s = 1,892.25
Rounding to the next whole number, we have:
N = 1,892
The pendulum does 1,892 oscillations between 8:00 am and 12:00 noon.
Atoms can create fields to interact with each other without touching.
True
or
False
Answer:
True
Explanation:
True, atoms create electromagnetic fields that form repulsion to keep them from touching.
A gas at a pressure p is compressed to half it original volume and twice its original temperature. The new pressure is
Answer:
4p
Explanation:
If you halve the volume the pressure will double as they are inversely proportional. If you double the temperature the particles have double the kinetic energy so the pressure will double again.
So:
p×2×2 = 4p
Answer:
P V = n R T
P2 V2 / (P1 V1) = T2 / T1
P2 = (T2 / T1) (V1 / V2) P1 = 2 * 2 = 4
Each tire on a car has a radius of 0.330 m and is rotating with an angular speed of 11.7 revolutions/s. Find the linear speed v of the car, assuming that the tires are not slipping against the ground. v
Answer:
The linear speed of the car, v, is 24.26 m/s
Explanation:
Given;
radius of the car's tire, r = 0.330 m
angular speed of the car, ω = 11.7 revolutions/s
The angular speed of the car in radian per second:
[tex]\omega = 11.7 \ \frac{rev}{s} \times \frac{2\pi \ rad}{1 \ rev} \\\\\omega = 73.523 \ rad/s[/tex]
The linear speed of the car, v, is calculated as;
v = ωr
v = 73.523 rad/s x 0.33 m
v = 24.26 m/s
Therefore, the linear speed of the car, v, is 24.26 m/s
In both the camera and the __________, light enters a narrow opening and is projected onto a photosensitive surface. Group of answer choices
Answer: The HUMAN EYE
Explanation:
The human eye is made up of different parts which ranges from controlling the amount of light that enters the eye to the focusing of the image that is formed. The camera is a device which is both mechanically and electronically operated which shares a number of similarities with the eye.
In the human eye, the IRIS helps to regulate the amount of rays passing through the pupil to the lens by either contracting or dilating in light or dark environment respectively. While in the camera, the DIAPHRAGM controls the amount of light entering the camera.
The PUPIL serves as the passage for light into the eye while in the camera, the APERTURE does the same.
The photosensitive surface in the eye is the YELLOW SPOT while in the camera, the photosensitive surface is the PHOTOGRAPHIC FILM.
When the motion of one or both of the particles is at an angle to the line of impact, the impact is said to be ________
Answer: Oblique impact
Explanation:
When the motion of one or both of the particles is at an angle to the line of impact, the impact is said to be oblique impact.
On the other hand, when the directions of motion of the two colliding particles are moving along a line of impact, then it's refered to as central impact.
Which of these would have the greatest pressure?
Group of answer choices
A large balloon with few gas molecules at a high temperature
A small balloon with many gas molecules at a low temperature
A small balloon with many gas molecules at a high temperature
A large balloon with few gas molecules at a low temperature
Hey, I'm a Turk. What language do you speak? I'm very curious.
Answer:
What languages do i sqeak?
English, Korean and Filipino
Uhh why are you asking it?
what is the efficiency of an engine that dies 288 J of work and exhausts 72 J of heat while taking 360 J of heat?
Answer:
80%
Explanation:
Energy Input: 360 J
Energy Output: 288 J
e= 288/360 × 100
e= 80%
Alternatively,
e= W(total)/ Q (in)
e= 288/360
e=0.8×100
e=80%
how much of the electro magnetic spectrum is visible to us
Answer:
The entire rainbow of radiation observable to the human eye only makes up a tiny portion of the electromagnetic spectrum – about 0.0035 percent. This range of wavelengths is known as visible light.
Explanation:
Please Mark me brainliest
(Serious Please) patulong
Answer:
a. Potential energy is highest at Part A
The kinetic energy is highest at Part C and Part D
b. The potential energy is lowest at Part C and Part D
c. The roller coater has equal amount of potential and kinetic energy at Part B, Part D and part F
2) Yes, the mechanical energy is the same from point A to F according to the first law of thermodynamics
Explanation:
The total mechanical energy is constant where the roller coaster moves by only the initial velocity, and the the force of gravity
Total mechanical energy, M.E. = Kinetic energy, K.E. + Potential energy, P.E.
M.E. = K.E. + P.E. = Constant
Therefore, we have;
a. Potential energy is the energy stored in a body, due to its position or elevation, state or arrangement
The higher the elevation, the higher the potential energy, therefore, the highest amount of potential energy is gained when the roller coaster is at the highest point in the motion = Part A
From M.E. = K.E. + P.E. = Constant, the highest kinetic energy is given at the point the roller coaster has the lowest potential energy, which corresponds with the lowest points = Part C and Part D
b. Potential energy, which is the energy of body due to its position or state is lowest at the lowest points = Part C and Part D
c. The value of potential energy, P.E. due to elevation, can be found as follows
P.E. = Mas, m × Gravity, g × Height, h
Therefore, the potential energy will be half the maximum value where the height, h = (Maximum height)/2 and given that M.E. = K.E. + P.E., the kinetic energy, will increase by the same amount, and we have;
K.E. = P.E. at the half the maximum height of the track = Part B, Part D and part F
2) The mechanical energy is the input energy, which according to the first law of thermodynamics cannot be created and destroyed an it is therefore, constant and it is the same from point A to F
Is it possible to get a body accelerated even if it is moving with uniform speed? justify.
Answer:Yes, A body can have constant speed but still accelerate as in case of uniform circular motion. In uniform circular motion speed remains constant and direction of velocity changes with every point in the direction of tangent drawn from that point.
Explaination:
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Calculate surface tension of an enlarged radius of 4cm to 6cm and amount of work necessary for enlargement was 1.5×10^-4 joules
Answer:
[tex]T=7.5*10^{-5}[/tex]
Explanation:
From the question we are told that:
Radius [tex]r=2cm[/tex]
Work done [tex]W=1.5×10^-4 joules[/tex]
Generally the equation for Work done is mathematically given by
[tex]W=T.dA[/tex]
Therefore
[tex]T=\frac{W}{dr}[/tex]
[tex]T=\frac{1.5*10^{-4}}{2}[/tex]
[tex]T=7.5*10^{-5}[/tex]
Which of the following statements are true with respect to the law of conservation of mass?
i) Mass is conserved during a chemical reaction.
ii) Amount of products formed can be determined using law of conservation of mass.
iii) Mass is destroyed during a chemical reaction.
O i only true
Both i and in
All three statements are true
All three statements are false
Answer:
Only (I) is true
i) Mass is conserved during a chemical reaction.
Which statement best describes how pigments affect what colors humans
see?
Answer:
the component of light reflected by that object
Explanation:
The Displacement is 5m. We found that using the
Pythagorean Theorem.
Vector Quantities require both a Displacement and a
Direction.
What direction is this Vector?
South
Northeast
West
Answer:
A vector can be written as:
(R, θ)
Where R is the magnitude, in this case, we know that the magnitude of the displacement is 5m
Then:
R = 5m
and θ defines the direction, it's an angle measured from the positive x-axis.
(In the image, θ would be the angle located at the point A)
Now, if you look at the image, you can see a triangle rectangle.
Where the adjacent cathetus has a length of 4,
the opposite cathetus has a length of 3 units
the hypotenuse has a length of 5 units.
So we can use any trigonometric rule to find the value of θ, like:
sin(θ) = (opposite cathetus)/hypotenuse
Then:
sin(θ) = 3m/5m
Now we can use the inverse sin function, Asin(x), in both sides
Asin( sin(θ)) = θ = Asin( 3/5) = 36.87°
then the vector is:
(5m, 36.87°)
Now, if we define the positive y-axis as the North, and the positive x-axis as the East.
This vector would point at 36.87° North of East.
(or almost Northeast)
In a softball game a batter hits at the velocity of 28 and an angle shown 45 below . What is the maximum range of the ball
Answer:
80 m
Explanation:
Given :
Initial Velocity, U = 28 m/s
θ = 45°
The maximum range occurs at angle, θ = 45°
The maximum range, R is given by ;
R = U²sin2θ / g
g = acceleration due to gravity = 9.8 m/s²
Plugging in the values :
R = [28² * sin2(45)] / 9.8
R = [28² * sin90] / 9.8
R = 784 / 9.8
R = 80 m
According to the principle that the emission lines of a substance must be at exact same positions of its absorption spectrum, what substance accounts for the dark lines in the absorption spectrum
Answer:
The dark lines in absorption spectrum of light is due capacity of atoms to absorb light of a specific energy. The absorption of light by atoms occurs when the atom transitions from a lower energy or ground state to an excited high energy state, and it appears in the emission spectrum of the element as dark lines located in the same position as the bright lines
Explanation:
A glass tube in the shape of a letter J has the shorter limb sealed and the longer limb open. Mercury is poured into the tube until the levels in either limb is the same when the tube is vertical.In this position, the length of the air column in the sealed limb is 6.3cm.More mercury is then poured into the tube until the length of the trapped air column is 42cm.Calculate the difference in the levels of mercury in the limbs if a nearby mercury barometer reads 75.0cm and the reading of a nearby thermometer has not changed?
Answer:
35.4 cm
Explanation:
We have that when the level of mercury on either limb is the same, the pressure of the trapped air, P₁ = Atmospheric pressure
Also the initial height of the mercury in the tube = The reading of the barometer = 75.0 cm
The initial length of the air column, l₁ = 6.3 cm
The final length of the air column, l₂ = 4.2 cm (The length is expected to decrease due to compression)
The volume, V = l × A
Where;
A = The cross sectional area of the tube
Therefore, the volume of the air column is directly proportional to the length of the air column
∴ V ∝ l
According to Boyles law, we have;
P₁·V₁ = P₂·V₂
Where;
P₁ = The initial pressure in the air column before more mercury is added
V₁ = The initial volume occupied by the air in the air column
P₂, and V₂ are the final pressure and volume of the air column respectively
Given that V = l·A, we can write;
P₁·l₁·A = P₂·l₂·A
P₂ = P₁·l₁·A/(l₂·A) = P₁·l₁/(l₂) = P₁ × 6.3/4.2 = 1.5·P₁
The pressure in the air column after more mercury is added, P₂ = 1.5 × P₁
P₁ = Atmospheric pressure, therefore;
The pressure in the air column after more mercury is added, P₂ = 1.5 × Atmospheric pressure
Pressure = h·ρ·g
Where;
ρ = The density of the substance
g = The acceleration due to gravity
h = The height of the column of the fluid
Given that the density and the gravitational force, can be taken as constant, we have that the pressure of the fluid is directly proportional to the height of the fluid column
Therefore, when the pressure doubles, the height of the fluid column doubles, and when the factor of increase is 1.5, we have;
The final level of the mercury, h₂ = 1.5·h₁ = 1.5×75 cm = 112.5 cm
The initial length of the closed end of the J tube, [tex]h_{closed1}[/tex] = 6.3 cm + 75 cm = 81.3 cm
The final length of the mercury in the closed end, [tex]h_{closed2}[/tex] = 81.3 cm - 4.2 cm = 77.1 cm
The difference in the level of mercury, Δh = h₂ - [tex]h_{closed2}[/tex]
∴ Δh = 112.5 cm - 77.1 cm = 35.4 cm
The difference in the levels of mercury in the limbs, Δh = 35.4 cm
A delivery boy on a bicycle drags a wagon full of newspapers by pedaling at 0.90 m/s for 45 minutes using a force of 40 N. How much work has the boy done?
Answer:
Explanation:
The equation for work is
W = FΔx
We are looking for work, so that means we have to be able to fill in the Force and the displacement. We have Force, but we don't have displacement. But the thing we need to do first is change the 45 minutes to seconds because the velocity is in m/s, not m/min.
45 minutes is 2700 seconds.
That means that the displacement is
Δx = (.90)(2700) so
Δx = 2430 m
Now we plug that in to find work, along with the given Force:
W = 40(2430) so
W = 97200 J (and that is not the correct number of sig fig's but I have a feeling you're not too into that in class, because if you were, the 40 N would be expressed as 40.0 or 4.0 × 10¹)
Are mass and weight the same thing?
Yes
No
Answer:
Explanation:
Definitely NOT! Mass is unchanging, wherever you go. On the moon you will have the same mass as you will on the earth. Mass is just a measure of the matter that makes up a body. Weight, however, is dependent upon the pull of gravity which is different on earth than it is on the the moon, for example.
Mass doesn't change with proximity whereas weight can.
Answer: No
Explanation: The terms'mass' and 'weight' are frequently used interchangeably, yet they have distinct meanings. Your mass remains constant regardless of where you are in the universe; nevertheless, your weight varies. The mass of anything is a measure of how much power is required to change its course.