Consider the sections of two circuits illustrated above. Select True or False for all statements. After connecting c and d to a battery, the current through R3 always equals the current through R4. Rcd is always less than or equal to R3. After connecting a and b to a battery, the voltage across R1 always equals the voltage across R2. Rab is always less than or equal to R1.

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.

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:

Answer:

B

Explanation:

Reason is that the suitcase is exerted downward and when it moves downward the equation is mgsin tita

Answer:

  [tex]v_{T}[/tex] = [tex]\frac{b}{m}[/tex]  g

Explanation:

For this exercise we use Newton's second law

         ∑ F = m a

where they relate it is

        a = dv / dt

        v = dx / dt

in this case we have two forces: the weight of the body and the friction of the air

       fr -W = m a

there are several ways to approximate the friction force in a fluid, if the velocity of the body is low we can use

       fr = b v

for high speeds, higher power speed terms are entered

we substitute

        b v - m g = m dv / dt

       [tex]\frac{dv}{dt}[/tex] = [tex]\frac{b}{m}[/tex] v -g

We can see that as the speed increases, we reach the point that the term on the right is zero, at this point there is no acceleration, therefore the speed is constant and is called the terminal velocity.

         0 =[tex]\frac{b}{m} \ v_T[/tex] -g

         [tex]v_{T}[/tex] = [tex]\frac{b}{m}[/tex]  g

the constant b is given by the conditions of the air, pressure, density and temperature

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.

Answer:

101.81818    MPH

Explanation:

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

Answer:

θ = 63.5º

Explanation:

       [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

       [tex]sin \theta_{i} = \frac{1.361}{1.520} = 0.895 (3)[/tex]

       ⇒   θi = sin⁻¹ (0.895) = 63.5º

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

Answer:

25.48

Explanation:

the earth's gravitational pull is 9.8 m/s. So to find the answer, multiply 2.6 x 9.8

Answer:

8.87 gallons of kerosene

Explanation:

Step 1: Given and required data

Step 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.

A concern which is related to the wind energy is that these could interfere with the pollen distribution. Thus, the correct option is D.

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.

Learn more about Wind energy here:

https://brainly.com/question/29293441

#SPJ6

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

Answer:

5.85 m/s²

Explanation:

Mass of pulley (M) = 6.8 kg, mass of bucket (m) = 1.5 kg, radius of pulley (r) = 0.816 m, acceleration due to gravity (g) = 10 m/s².

Let the tension exerted on the pulley be T and the angular acceleration be α,

The angular acceleration (α) = a / r; where a is the linear acceleration.

mg - T = ma

T = m(g - a)

Also, for the disk:

Tr = Iα

I = moment of inertia = 0.5Mr²

m(g - a)r = 0.5Mr²(a/r)

m(g - a)r = 0.5Mra

2m(g - a) = Ma

2mg - 2ma = Ma

Ma + 2ma = 2mg

a(M + 2m) = 2mg

a = 2mg / (M + 2m)

Substituting:

a = 2(3.1 kg)(10 m/s²) / (4.4 + 2(3.1))

a = 5.85 m/s²

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

Answer:

16N

Explanation:

Answer:  3.2 kilograms

=================================================

Work Shown:

Apply 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

Answer:

a group of organs working together to perform a function.

Explanation:

Answer:

Explanation:

A compound machine is a combination of two or more simple machines.

BRAINLIEST? plz

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:

Answer:

   v =[tex]\sqrt{\frac{k}{m} }[/tex]    x

Explanation:

For this exercise let's use the important topic of conservation of energy

starting point. Spring compression point

          Em₀ = K_e = ½ k x²

final point. When the spring is not compressed

          Em_f = K = ½ m v²

as they indicate that there is no friction, the energy is conserved

          Em₀ = Em_f

          ½ k x² = ½ m v²

          v =[tex]\sqrt{\frac{k}{m} }[/tex]    x

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

Answer:

Explanation:

Given;

initial velocity of the ball, u = 30 m/s

final velocity of the ball at the highest point, v = 0

The maximum height reached by the ball is calculated as;

v² = u² - 2gh

where;

h is the maximum height reached by the ball

0 = 30² - (2 x 9.8)h

19.6h = 900

h = 900 / 19.6

h = 45.92 m

Time taken to fall to half of its height is calculated as;

when falling down, the final velocity v becomes the initial velocity = 0.

Apply the following kinematic equation;

h = ut + ¹/₂gt²

h = 0 + ¹/₂gt²

h = ¹/₂gt²

where;

h = 45.92 m is the maximum height reached

half of h = 45.92 / 2 = 22.96 m

22.96 = ¹/₂gt²

[tex]t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2\times 22.96}{9.8} }\\\\t = 2.2 \ s[/tex]

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.

answer:

electric discharge takes place at low pressure because a small electric field is required.

explanation:

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 -

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.

Learn more about wind energy here:

https://brainly.com/question/26117202

Answer:

(2).........

Explanation:

(2)..........

Answer:

D

Explanation:

Have a great day ;)