Answer:
Ra / Rb = 3
Explanation:
The resistance is defined by the expression
r = ρ L / A
where A is the area of the wire and L is the length
let's find the area of each wire
a) solid wire (A) of d₁ = 1 m
r = d₁ / 2 = 0.5 m
A = π r²
A = π 0.5²
R_a = [tex]\frac{\rho \ L}{\pi \ 0.5^2}[/tex]
R_a = 4 \frac{\rho \ L}{\pi }
b) hollow tube (B) of d₁ = 1 m and d₂ = 2m
the radios are
r₁ = 0.5 m
r₂ = 1 m
the area is
A = π r₂² - π r₁²
A = π (r₂² - r₁²)
A = π (1² - 0.5²)
A = π 0.75
resistance is
R_b = [tex]\frac{ \rho \ L }{\pi \ 0.75}[/tex]
R_b = 1.33 \frac{ \rho \ L }{\pi }
therefore the relationship between these two resistances is
Ra / Rb = 4 / 1.33
Ra / Rb = 3
A battery connected to two wires in parallel. Both wires are made of the same material and are of the same length, but the diameter of wire A is twice the diameter of wire B.
True or False for the following:
1) The resistance of wire B is four times as large as the resistance of wire A.
2) The power dissipated in wire A is 16 times the power dissipated in wire B.
3) The voltage drop across wire B is larger than the voltage drop across wire A.
4) The resistance of wire B is twice as large as the resistance of wire A.
5) The current through the battery is five times larger than the current through wire B.
Answer:
true 1
2 is false 2. 3 . 4. 5
Explanation:
For this exercise, let's calculate the different parameters and analyze the corresponding statements.
the resistance of each wire
R = ρ [tex]\frac{L}{A}[/tex]
wire B.
has a diameter of d₀
therefore its radius is r₀ = d₀ / 2
the area is A = pi r₀²
A = π d₀²/ 4
we subtitle
Ro = ρ [tex]\frac{L \ 4}{\pi d_o^2}[/tex]
R_b = R₀
wire A
the diameter is d = 2d₀
therefore the radius is r = d/2
r = d₀
resistance is
R_a = ρ [tex]\frac{L}{\pi d_o}[/tex]
R_a = 4 R₀
when examining the answers
1 is true
4 is false
Now let's calculate the power
P = V I
V = I R
P = V² / R
as they indicate that the cables are connected in parallel, the voltage in them is the same, therefore the potency depends on the resistance
wire B
P = V² / R_b
P_b = V² / R₀
wire A
P_a = v² / R_a
P_a = V² / 4R₀
P_a = ¼ P_b
2 is false
in a parallel circuit the waves are the same therefore
3 False
ohm's law is
V = I r
I = V / R
wire B
I_b = V / R_b
I_b = V / Ro
wire
I_a = V / R_a
I_a = V / 4 Ro
I_a = ¼ I_a
5 is false
explain the principle of N-type semiconductor
Answer:
Explanation:
An N-type semiconductor is a type of material used in electronics. It is made by adding an impurity to a pure semiconductor such as silicon or germanium. The impurities used may be phosphorus, arsenic, antimony, bismuth or some other chemical element. They are called donor impurities
How do intermolecular forces (IF) and internal kinetic energy (KE) compare in gases?
IF = 0, KE is large
IF < KE
IF ≥ KE
IF > KE
Please help me!
Answer:
IF < KE
Explanation:
The kinetic energy of the gas is greater than the intermolecular forces making the molecules have room to move around without disruption. In a lot of gases, there are sometimes no intermolecular forces between all the particles.
Best of Luck!
An uncharged capacitor and a resistor are connected in series with a switch and a 12 V battery. At the instant the switch is closed, the voltage across the resistor is
Answer:
V = 12 V
Explanation:
Since a capacitor can't change the voltage between its plates instantaneously, this means that just after the switch is closed, the voltage through the capacitor is zero.So, the current that flows in this moment is the same that would flow in a series circuit with only one resistor connected to the battery.Applying KVL to the circuit (neglecting the presence of the capacitor which can be replaced by a short circuit just after closing the switch), the voltage through the resistor must be equal to the one of the battery, i.e., 12 V.A 2 kg melon is balanced on your bald uncle’s head. His son, Throckmorton, shoots a 50 g (0.05kg) arrow at it with a speed of 30 m/s. The arrow passes through the melon and emerges with a speed of 18 m/s. Find the speed of the melon as it flies off the man’s head.
Answer:
The speed of the melon as it flies off the man’s head is 0.3 m/s.
Explanation:
Given;
mass of the melon, m₁ = 2 kg
initial speed of the melon, u₁ = 0
mass of arrow, m₂ = 0.05 kg
initial speed of the arrow, u₂ = 30 m/s
final speed of the arrow, v₂ = 18 m/s
let v₁ be the final speed of the melon as it flies off the man's head.
Apply the principle of conservation of linear momentum;
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
2(0) + 0.05 x 30 = 2v₁ + 0.05 x 18
1.5 = 2v₁ + 0.9
2v₁ = 1.5 - 0.9
2v₁ = 0.6
v₁ = 0.6 / 2
v₁ = 0.3 m/s
Therefore, the speed of the melon as it flies off the man’s head is 0.3 m/s.
Select the correct answer.
A car is moving at a constant speed along a straight line. Which statement is true about the forces acting on the car?
ОА.
The net force acting on the car from all directions is zero.
o
B.
The net force acting on the car is greater than the car's weight.
O c.
The net force acting on the car is in the direction of the car's motion.
OD.
The net force acting on the car is in the opposite direction of the car's motion.
Answer:
ОА.
The net force acting on the car from all directions is zero.
Explanation:
Constant speed along a straight line
It means constant magnitude of velocity without chainging direction
It means constant velocity. Which means acclecration is zero
By Newton's second law:
[tex]F=ma[/tex]
Net force is also zero
Part A Every force has one and only one 3rd law pair force. Every force has one and only one 3rd law pair force. true false Request Answer Part B The two forces in each pair act in opposite directions. The two forces in each pair act in opposite directions. true false Request Answer Part C The two forces in each pair can either both act on the same body or they can act on different bodies. The two forces in each pair can either both act on the same body or they can act on different bodies. true false
Answer:
Explanation:
Part A
Every force has one and only pair force , according to 3 rd law
It is true , the pair force has equal magnitude .
Part B
The two forces in each pair act in opposite directions.
It is true .
The pair forces are equal and act in opposite direction .
Part C
The two forces in each pair can either both act on the same body or they can act on different bodies.
It is false .
The two forces in each pair can not act on same body . They act on different bodies , bodies which are undergoing mutual interaction.
A hamster eats a carrot before using its hamster wheel. The hamster wheel is connected to a generator which powers a light bulb.
Mechanical → Chemical → Radiant → Electrical
Chemical → Mechanical → Electrical → Radiant
Chemical → Mechanical → Thermal → Electrical
Mechanical → Electrical → Thermal → Radiant
Answer: Chemical → Mechanical → Electrical → Radiant
Explanation:
First, the Hamster eats the carrot, then the hamster is getting chemical energy.
Now the hamster starts using his wheel, then he "transforms" the chemical energy into mechanical energy.
Now the mechanical energy is connected to a generator, this means that the mechanical energy (the rotation of the wheel) is being converted into electrical energy.
And we know that there is a light bulb powered by this electrical energy, then we have electrical energy being transformed into radiant energy.
Then the correct option is:
Chemical → Mechanical → Electrical → Radiant
why all traveller prefer to travel easily in the morning and night and not when the sun is hot
Answer:
Travelers prefer to travel in morning because arthat time the temperature ️ is not too hot and they can easily travel here and there without any problem. and they also prefer to travel in night because moderate temperature ....
What causes an electromagnet to create a magnetic field?
A.The Earth's magnetic field.
B.The poles are attracted to each other.
C.The iron is wrapped with a coiled wire.
D.There is a current flowing through the wire.
Answer:
D
Explanation:
Have a great day ;)
a. Describe the big bang theory. (1 point) b. Match each model of the universe with the future it predicts. (1 point) A. Closed B. Flat C. Open _____ The universe will stop expanding but will not collapse. _____ The universe will continue to expand forever. _____ The universe will stop expanding and then collapse back to its point of origin. c. Match each observation to the conclusion it supports in the big bang theory. (1 point) A. Light from other galaxies is shifted toward the red end of the spectrum. B. Cosmic background radiation appears uniform across the sky. C. The amount of helium in the universe matches predictions. _____ Nucleosynthesis of light elements occurred shortly after the expansion of the original ball of energy. _____ The universe is expanding. _____ The universe began from a single point.
Answer:
A)
The Big Bang is the earliest known event in the observable Universe, its earliest known phase of evolution, and the name of the model for this process. According to this scenario, the Big Bang took place around 13.800 million years ago, when the known Universe emerged from very dense and hot matter. This theory is based on observations showing that space is expanding from an initial state where all the matter in the universe had a very high density and temperature, to a more cold and stable one.
B)
A. Closed. The universe will stop expanding and then collapse back to its point of origin.
B. Flat. The universe will stop expanding but will not collapse.
C. Open. The universe will continue to expand forever.
A ball is thrown up into the air. The time that it takes to go up equals
Answer:
The time it takes the ball to rise equals the time it takes to fall.
Explanation:
because what goes up at some point must come down
A glass optical fiber is used to transport a light ray across a long distance. The fiber has an index of refraction of 1.520 and is submerged in ethyl alcohol, which has an index of refraction of 1.361. What is the critical angle (in degrees) for the light ray to remain inside the fiber
Answer:
θ = 63.5º
Explanation:
When a ray of light strikes the separation surface between two transparent media with different index of refraction, part of the light remains in the first medium, and part transmits to the second one , according to the Snell's Law, as follows:[tex]sin \theta_{i}* n_{i} = sin \theta_{r}* n_{r} (1)[/tex]
where θi = angle of incidence (with the normal to the surface)
θr = angle of refraction (with the normal to the surface)
ni = index of refraction of denser medium = 1.520
nr = index of refraction of less dense medium = 1.361
When the angle of refraction is equal to a right angle, this means that the light is parallel to the surface, and remains within the first medium completely.The angle of incidence for this particular angle, is called the limit angle, and is the principle of operation of fiber optics, which are composed by a strand of glass, surrounded with another material, which index of refraction is lower than the fiber's, preventing light to go outside the fiber.In our case, replacing ni, nr, and θr = 90º in (1), we get:[tex]sin \theta_{i}* 1.520 = 1* 1.361 (2)[/tex]Solving for sin θ₁ :[tex]sin \theta_{i} = \frac{1.361}{1.520} = 0.895 (3)[/tex]
⇒ θi = sin⁻¹ (0.895) = 63.5º
Which choices describe advantages of wind energy over fossil fuels?
Select all that apply.
doesn't emit pollutants
renewable
freely available
O releases carbon dioxide instead of carbon monoxide
The advantages of wind energy over fossil fuels are that it does not emit pollutants, it is a renewable source of energy and it is a freely available source of energy.
What is wind energy?
The process that describes the generation of wind power or the mechanical power using the flow of wind itself, is known as wind energy.
Following are the advantages of wind energy over fossil fuels -
Free source of fuel.One of the cleanest forms of energy.Advance technologies are used for its extraction.Does not disrupt any sort of farmland operations.It is a clean fuel source and does not emit pollutants.It is a renewable source of energy.Thus, we can conclude that the advantages of wind energy over fossil fuels are that it does not emit pollutants, it is a renewable source of energy and it is a freely available source of energy.
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Describe what Rutherford would have seen in his gold foil experiment if J.J. Thompson's Plum Pudding model was completly accurate.
Answer: i use this in ss class
Explanation:
Does solar/light energy explain why/how thing keep going?
O Yes, solar/light energy can convert into other kinds of energy that makes things go, such as TE, ELE, and CE
O No, solar/light energy canonly power solar panels, so it cannot serve as a source of why things go
.
Answer:
In 1954 modern solar cells were invented at Bell Labs with the intent of powering satellites. For many years solar remained expensive but today prices have come down and solar electricity is everywhere. Our satellites and the Mars rover are solar powered, as are homes, toys, outdoor lighting and solar battery packs to charge our electronic devices. Importantly solar electricity is bringing light to the one billion people around the world who live without power. Often these solar lights are replacing kerosene or candles as light sources in the home. Let’s look at some frequently asked questions about solar lights and how they are changing the world.
What are solar lights made of? Solar lights are made up of four main components: the solar photovoltaic (PV) panel, battery, control electronics and the light fixture. When the sun is out, a solar panel takes the light from the sun and produces electrical energy. The energy can then be used immediately or stored in a battery. The goal of most solar lights is to provide power at night, so they will definitely contain a battery, or be capable of attaching to a battery. The battery itself may not need to have a large capacity, due to the availability of solar energy, but it should be long lasting to account for difficulties replacing batteries in many places across the globe.
The advent of the Light Emitting Diode (LED) for the light fixture has drastically reduced the capacity needs of both the solar panels and the batteries. They use significantly less energy than other types of lighting, so the solar panel and battery can be smaller (more transportable and less expensive). The control electronics are required to move the energy around the system, keep the system safe, and potentially switch on or off your light, depending on the level of light it’s exposed to. Solar lights made for outdoor lighting will often turn on automatically when it gets dark outside. Some solar lights made for reading will turn off during daylight hours to preserve the solar charge, but won’t turn on until they are powered on by a user.
How is solar energy produced? Let’s look a little more deeply into the science behind solar electricity. Solar energy is produced due to the photovoltaic effect. A photovoltaic panel (also known as solar cell) converts sunlight into electrical energy. The solar cell is made up of multiple layers of crystalline silicon and chemicals that create layers of negatively-charged electrons and positively-charged spaces. When light passes through the solar cell, it excites the negatively-charged electrons and pushes them into the positively-charged spaces. Those spaces then transfer the electron stream as direct current of electricity through the wires in the solar cell for use or to a battery where the power is stored until it is needed.
Explanation:
Friction occurs when microscopic hills and valleys stick together
true or false
Answer:
true
Explanation:
Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
Explanation:
true but not going to copy and paste,
Hail stones mostly melts unto rain during the fall from the sky why?
Answer:
(2).........
Explanation:
(2)..........
liquids have higher coefficents of expansion than solids do in general. ture or false worth 29 points!
Answer:
true
Explanation:
How is the chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe)?
A.
In an iron crystal, the atoms are joined by sharing electrons. In carbon dioxide, atoms of carbon and oxygen are held together by freely moving electrons.
B.
In a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons.
C.
In an iron crystal, the atoms are joined by their opposite electrical charges. In carbon dioxide, atoms of carbon and oxygen are held together by freely moving electrons.
D.
In a carbon dioxide molecule, atoms of carbon and oxygen are joined by their opposite electrical charges. In an iron crystal, the atoms are held together by freely moving electrons.
Answer:
I'ts B
Explanation:
:p
The chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe) in a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons. Therefore, option B is correct.
What is chemical bonding ?The term chemical bonding is defined as the formation of a chemical bond between two or more atoms, molecules, or ions to form a chemical compound.
There are three main types of chemical bonding that are ionic bonding, covalent bonding, and metallic bonding.
The chemical bonding within a molecule of carbon dioxide (CO2) different from the chemical bonding within a crystal of iron (Fe) because in a carbon dioxide molecule, atoms of carbon and oxygen are joined by sharing electrons. In an iron crystal, the atoms are held together by freely moving electrons.
Thus, option B is correct.
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10/12
11.
You drive the 10 miles to the mall at an average speed of 40 mph. On
the way home, you hit severe traffic and had to drive at an average
speed of 10 mph. What is your average speed for the trip?
Which choice describes a concern with wind energy?
O may harm bird and bat populations
o negative impact on river ecosystems
O turbines are cheaply made
O could interfere with pollen distribution
A concern which is related to the wind energy is that these could interfere with the pollen distribution. Thus, the correct option is D.
What is Wind energy?Wind power or wind energy is mostly used in the wind turbines to generate electricity. The wind power is a popular, sustainable, renewable energy source which has a much smaller impact on the surrounding environment than that of burning fossil fuels.
Some disadvantages of wind energy include noise and visual pollution, wind power is not a remote power, and the effects or impact on the environment including interference with the pollen distribution.
Therefore, the correct option is D.
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A 5 kg block rests on a rough horizontal table. A rope is
attached to the block and is pulled with a force of 11N to the
left. As a result, the block accelerates at 2 m/s2. The coefficient
of kinetic friction between the block and the table is (round
to the nearest hundredth)
Answer:
Approximately [tex]0.02[/tex] (assuming that [tex]g = 9.81\; \rm N \cdot kg^{-1}[/tex], and that the block was initially moving to the left.)
Explanation:
Apply Newton's Second Law to find the net force on this block.
Mass of this block: [tex]m = 5\; \rm kg[/tex].
Acceleration of this block: [tex]a = 2\; \rm m \cdot s^{-2}[/tex].
[tex]\begin{aligned}\text{Net force} &= m \cdot a \\ &= 5\; \rm kg \times 2\; \rm m \cdot s^{-1} = 10\; \rm N\end{aligned}[/tex].
The block is moving and accelerating towards the left. Hence, friction (which opposes motion) would be towards the right and would be opposite to the direction of the [tex]11\; \rm N[/tex] pulling force.
Therefore, the expression for the net force on this object would be:
[tex](\text{Net force} ) = (\text{Pulling force}) - (\text{Friction})[/tex].
[tex]10\; \rm N = 11\; \rm N - (\text{Friction})[/tex].
Hence:
[tex]\text{Friction} = 11\; \rm N - 10\; \rm N = 1\; \rm N[/tex].
The question states that this table is horizontal. Weight of the block (downwards) and normal force from the table (upwards) are the only two forces on this block in the vertical direction. Hence, the magnitude of the normal force on this block would equal to that of the weight of the block:
[tex]\begin{aligned} |\text{Normal force}| &= |\text{Weight}| \\ &= m \cdot g \\ &= 5 \; \rm kg \times 9.81\; \rm N \cdot kg^{-1} = 49.05\; \rm N\end{aligned}[/tex].
Calculate the constant of kinetic friction between this block and the table:
[tex]\begin{aligned}\mu_{\text{k}} &= \frac{\text{Friction}}{\text{Normal force}} \\ &= \frac{1\; \rm N}{49.05\; \rm N} \approx 0.02\end{aligned}[/tex].
An 8 N force accelerates an object at a rate of 2.5 m/s what Is the mass of the object
Answer:
16N
Explanation:
Answer: 3.2 kilograms
=================================================
Work Shown:
F = 8 newtons = force appliedm = unknown mass in kilogramsa = 2.5 m/s^2 = accelerationApply Newton's Second Law of Motion
F = m*a
8 = m*2.5
2.5m = 8
m = 8/2.5
m = 3.2
The mass is 3.2 kilograms
what is the combination of two or more simple machine
Answer:
compound machineExplanation:
A compound machine is a combination of two or more simple machines.
BRAINLIEST? plz
why is a simple cell importable
REALICE UN ANALISIS DEL TEMA, INDICANDO LAS IDEAS PRINCIPALES
Answer:
De cual Tema??? jajaja no se que necesitas
Answer:
El análisis temático es un método de análisis de datos cualitativos. Por lo general, se aplica a un conjunto de textos, como las transcripciones de entrevistas. El investigador examina de cerca los datos para identificar temas comunes: temas, ideas y patrones de significado que surgen repetidamente.
Explanation:
does the sabre-tooth currirulum still exist at present?give examples of your evidence
Answer: Should the sabre tooth curriculum really exist at the moment? As far as I am concerned, the sabre tooth program should remain, because our school system needs to help people know how to do complex activities on their own and we let them do activities that will help them develop their brains as well as their skills.
Great schools promote better teaching because they have the most experience of teaching practice and are accountable for executing the instruction in the classroom. Teacher engagement is also vital for the effective and substantive implementation of the curriculum.
Sources: files.eric.ed.gov and James Kennedy Monash
You are traveling on a plane trip from Washington, D.C. to Cleveland, Ohio and the plane uses 1,260 MJ/passenger trip. If you made the trip by car it would take 18 gallons/passenger trip. There are 142 MJ in a gallon of kerosene, a type of jet fuel. How many gallons of kerosene does it take to make the trip by plane?
Answer:
8.87 gallons of kerosene
Explanation:
Step 1: Given and required data
Energy to travel by plane per passenger trip: 1,260 MJ/passenger tripEnergy per gallon of kerosene: 142 MJ/galStep 2: Calculate how many gallons of kerosene it takes to make the trip by plane
We can calculate the amount of kerosene required by combining the factor provided in Step 1.
1 gal/142 MJ × 1,260 MJ/passenger trip = 8.87 gal/passenger trip
8.87 gallons of kerosene are required to make the trip by plane.
How long will it take a 200kg stationary man in space to travel 20m if he throws a 10 kg object at a velocity of 30m/s?