Please help

how long have people used coal as a source of fuel
A. 200 years
B. 1000 years
C. 3000 years
D. 5000 years

Answers

Answer 1

Answer:

c. 3,000

Explanation:

I am guessing 3000 years


Related Questions

Which force is responsible for holding the nucleus together via gluons.

Answers

The strong nuclear force holds together the protons and neutrons in the nucleus of an atom

The photograph shows a kettle made of the element copper. Which statement describes a chemical property of copper?

A. Copper forms a patina when it interacts with air.

B. Copper is a solid at room temperature.

C. Copper is a good conductor of electric current.

D. Copper can be re-shaped when hit with a hammer.

Answers

A copper forms a patina when it interacts with air
Answer A
Explanation
B describes its matter (composition)
C describes its ability to conduct
D describes is mailability

A describes a chemical reaction with the air

A monochromatic light passes through a narrow slit and forms a diffraction pattern on a screen behind the slit. As the slit width increases, the diffraction pattern:.

Answers

As the slit width increases, the diffraction pattern gets narrower and vice versa.

Relationship between width and diffraction pattern

The increase in silt width leads to the narrowing of diffraction pattern of the  light because the increase of width reduces the space for the passing of light wave.

So we can conclude that as the slit width increases, the diffraction pattern gets narrower and vice versa.

Learn more about diffraction here: https://brainly.com/question/16749356

5. The amount of energy provided by a battery in a circuit is
the amount of energy consumed in the circuit.

A. Equal to
B. Less than
C. Greater than
D. Not related to

Answers

Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second. So the answer is C
5. The amount of energy provided by a battery in a circuit is
the amount of energy consumed in the circuit.

C. Greater than

26. Suppose you have a circuit with two lightbulbs that have the same resistance
connected in series and you have another circuit with two lightbulbs with the same
resistance connected in parallel. What would happen if you disconnected one bulb in
each circuit?

Answers

Answer:

It would break the circuit.

Explanation:

What do we mean by the diffraction limit of a telescope?.

Answers

Answer:

Diffraction Limit. The angular resolution that a telescope could achieve if it were limited only by the interference of light waves; it is smaller (i.e., better angular resolution) for larger telescopes.

Explanation:

Searched it up

Help!!
Hurry!!!?!?!?
I don't know!!!!!​

Answers

Answer:

KE = 1/2 M V^2 = 35 kg / 2 * (10 m/s)^2

KE = 17.5 * 100 kg m^2 / s^2 = 1,750 Joules

(B) is the correct answer

The Earth pulls on the Sun with the same magnitude force that the Sun pulls on the Earth. If these forces are equal, why does Earth go in orbit around the Sun? Why does Earth experience a great centripetal acceleration, while the Sun doesn't?

Answers

Answer:

For every force there is an equal and opposite reaction force.

For instance, if one wants to find the acceleration of a person standing on a scales, he uses the force exerted by the scales on the person,

One doesn't consider the reaction force of the person on the scales.

Likewise for the force of the sun on the earth

m v^2 / R = G M m / R^2 descibes the force acting on the earth to produce the centripetal acceleration of v^2 / R

The sun experiences the same centripetal acceleration as the earth, but since the mass of the sun is about 333,000 times the mass of the earth the acceleration can be ignored for most purposes.

When a satellite experiences an acceleration of v^2 / r, the earth is undergoing the same centripetal acceleration. However since the mass of the earth is much greater than that of a satellite and the centripetal acceleration of the earth is ignored.

A 430 kg piano is to be slid up a 3.5 m frictionless plank at a constant speed. The plank makes an angle of 30° with the horizontal. Calculate the work done by the person sliding the piano up the plank.

Answers

Answer:

10628.87 1

Explanation:

As the projectile goes upward, what energy changes take place?.

Answers

Answer:

Initial kinetic energy is transformed into potential energy.

define physical balance​

Answers

A physical balance is simply a weight measuring instrument. It is used to measure the weight of any unknown object with the help of the other object with known weight.

Explanation:

Hope it helps you!!

7. A rocket has a weight of 30,000 N on earth. a) What is the mass of the rocket in outer space? Use appropriate calculations and arguments to support your answer.
b) Calculate the weight of the rocket on planet X (g=7.5 N/Kg)
c) What is the weight of the rocket in outer space? Provide reasons to support your answer

Answers

Explanation:

a) mass=3000kg

b) weight on planet x=3000 × 7.5

=22,500N

c) Weight in outer space will be equal to zero

since the gravity in outer space is negligible

a bullet of mass 50gm is moving with the velocity of 720 km / HR calculate the key of bullet

Answers

Answer:

1000 j

Explanation:

KE = 1/2 m v^2        where m is in kg and v = m/s

    = 1/2 * .050 * (720 *1000/3600 )^2

The graph represents the relationship between the work done by a student running up a flight of stairs and the time of ascent.

I think the answer is B, I think im wrong.

Answers

Answer:

power

Explanation:

The slope would be  y/x    or   work / time   which is the definition of power

Do people actually see me inverted?☹​

Answers

Answer:

of course is clear

Explanation:

very clear

Questions #11, 12, and 13:

Part 1 of 3: 2.4 cm³ of water is boiled at atmospheric pressure to become 4514.7 cm³ of steam, also at atmospheric pressure. Calculate the work done by the gas during this process. The latent heat of vaporization of water is 2.26 × 10⁶ J/kg. Answer in units of J.

Part 2 of 3: Find the amount of heat added to the water to accomplish this process. Answer in units of J.

Part 3 of 3: Find the change in internal energy. Answer in units of J.

Answers

During the isobaric expansion;

work done by the gas is 457.2 Jheat absorbed by the water is 4520 Jthe change in internal energy of a system is 4062.8 J.

What is the work done by a gas in an isolated process?

The work done by a gas in an isolated expansion is the product of pressure and change in volume.

[tex]W = p\times \Delta V[/tex]

1 atm = 101325 Pa

2.4 cm³ = 2.4 × 10^-6 m³

4514.7 cm³ = 4514.7 × 10^-6 m³

[tex]W = 101325 Pa \times (4514.7\times 10^{-6} m^3 - 2.4\times10^{-6} m^3) = 457.2 J \\ [/tex]

Thus, work done by the gas is 457.2 J

Tje Heat absorbed by the water during vaporization process is calculated using the formul:

Q = m×ΔHvap

mass of water = density × volume

mass of water = 1 g/cm³ × 2.4 cm³ = 2 g = 0.002 kg

Q = 0.002 kg × 2.26 × 10⁶ J/kg

Q = 4520 J

Thus, heat absorbed by the water is 4520 J

The change in internal energy, ΔU of a system is given as the heat absorbed minus the work done by the system.

[tex]\Delta U = Q-W [/tex]

ΔU = 4520 J − 457.2 J = 4062.8 J

Therefore, the change in internal energy of a system is 4062.8 J.

Learn more about change in internal energy at: https://brainly.com/question/14126477

Use the passage to answer the question.

Light can be passed through two slits and projected onto a screen. The light from the two light sources produces a pattern of dark and light spots on the screen. The spots can be the result of interference, which happens with waves but not particles. This shows that the wave explanation is best for explaining the spots.

What is the reasoning in this passage?

(1 point)

Light can be passed through two slits and projected onto a screen.


The light from the two light sources produces a pattern of dark and light spots on the screen.


The spots are the result of interference, which happens with waves but not particles.

This shows that the wave particle is best for explaining the spots.

Answers

The reasoning in the passage is : ( C ) The spots are the result of interference, which happens with waves but not particles

Light waves

Light passed through a slit and projected onto a screen will form a pattern which is very visible and the pattern might have dark spots if there is some form of interference. Interference is present in waves and not particles.

Hence we can conclude that the reasoning in the passage is The spots are the result of interference, which happens with waves but not particles

Learn more about light waves : https://brainly.com/question/25847009

Which term is used to describe the highest point on a transverse wave?

A. frequency

B. crest

C. trough

D. amplitude

Answers

Answer:

B. Crest

Explanation:

The high point of a transverse wave is a called the crest.

Which purpose does a light bulb serve in a circuit?

Answers

Answer:

A light bulb is that component of circuit that lights up when electricity flows through it and vice versa. Its main function is to tell whether electricity is being supplied or not. Its function is also to light up dark places.

Explanation:

Answer:

A light bulb is that component of circuit that lights up when electricity flows

Explanation:

initial velocity 0 km/hr, final velocity 24km/hr, time 3s, what is acceleration

Answers

Answer:

8 km/hr

Explanation:

Acceleration

=Change in Velocity/ Time

=(24-0)/3

=8

The acceleration of the body is {a} = 8 km/hr².

What is acceleration?

Acceleration is defined as the rate of change of velocity per unit time.

Given is -

Initial velocity : 0 km/hr

Final velocity : 24km/hr

Time : 3s

We can write the acceleration as -

a = Δv/Δt

a = (24 - 0)/(3 - 0)

a = 24/3

a = 8 km/hr²

Therefore, the acceleration of the body is {a} = 8 km/hr².

To solve more questions on acceleration, visit the link -

brainly.com/question/30098550

#SPJ2

How many times has the Sun orbited around the Milky Way since the Sun first formed, if the Sun makes one orbit every 231 million years

Answers

Answer:

It would depend on the amount of years.

Explanation:


I don’t think this is very helpful-

Have a great day!

Anygays-

A hiker, weighing 560 newtons, takes 140 seconds to walk to the top of a hill with a height of 60 meters. How much power does the hiker develop?

A. 240 W

B. 1300 W

C. 2400 W

D. 78,000 W

Answers

Answer:

A -- 240

Explanation:

It takes around 270 to cycle more newtons up a hill

conventionally anti clock wise torque is taken as?

Answers

Answer:

An anti-clockwise movement is taken as a positive and a clockwise moment is taken as a negative.

A block is sitting on a small platform supported by a spring and is undergoing simple harmonic oscillation with a frequency of 4.5 Hz. What is the maximum amplitude at which the block will stay on the platform

Answers

For a block undergoing simple harmonic oscillation, the maximum amplitude is mathematically given as

a=0.0749m

What is the maximum amplitude at which the block will stay on the platform?

Generally, the equation for the maximum acceleration is mathematically given as

Ma=A*w^2

Where

A = 0.075 m

Therefore

0.075 * w^2 = 9.8

w = 11.43 rad/s

In conclusion, maximum frequency

mF=w/2pi

mF=11.43/2pi

mF= 1.82 Hz

Where

g=2\pif)^2a

a=(9.8)/4*\pi^2(1.82)^2

a=0.0749m

Read more about frequency

https://brainly.com/question/24623209  

If a bullet of mass 50 gm is moving with the velocity of 720 km/hr. Calculate its kinetic energy. Ans: here, mass (m)= 50 gm = 50/1000 kg = 0.05 kg velocity (v) = 720 km/hr= 720×1000/60×60=200m/s kinetic energy = ? We know, K.E.= 1/2 mv^2 = 1/2 × 0.05×(200)^2 = 0.05×40000/2 = 1000j ans. Is it correct???????

Answers

Answer:

yes   1000 j   as I posted on the same Q elsewhere

Explanation:

A sound travels down a hallway that is 115 m long. Then it echoes and
returns back to the source. If the speed of sound is 350 m/s, how long
does it take in seconds) to hear the echo?

Answers

Answer:

0.66 s

Explanation:

∆x = v∆t → 2 × 115 = 350 ∆t → ∆t = 230/350 = 0.66 s

Why is the speed of different sounds in a single medium remain the same though wavelength is different?

Answers

Answer:

I think it's because the refractive index of that medium is constant

One end of a copper rod is placed in a flame of a Bunsen burner. Small pieces of wax placed along the rod melt at progressively larger distance from the flame. Heat is transferred through the rod by ________.

1) Convection
2)Radiation
3)Conduction​

Answers

3) Conduction

Conduction is the process of heat transferring from a region of hotter temperature to a region of colder temperature through a material or substance by its atoms or molecules transferring heat energy to each other through collision

Hope this helps

Answer:

3) Conduction

Explanation:

When heat is transferred through a material, it can be referred to as conductionThe wax on the rod can only melt by the rod only if it is in contact with it

Compressed air moves through a pipe at a speed of 0.5m/s. If the diameter is 1 cm, what is the flow rate of the air

Answers

Answer:

Square the pipe's radius. With a radius, for instance, of 0.05 meters, 0.05 ^ 2 = 0.0025. Multiply this answer by the pressure drop across the pipe, measured in pascals. With a pressure drop, for instance, of 80,000 pascals, 0.0025 x 80,000 = 200.

Explanation:

I hope this helps!

why do we see optical illusion?​

Answers

Optical illusions occur because our brain is trying to interpret what we see and make sense of the world around us. Optical illusions simply trick our brains into seeing things which may or may not be real.

Optical illusions occur because our brain is trying to interpret what we see and make sense of the world around us. Optical illusions simply trick our brains into seeing things which may or may not be real.
Have a great day ;)
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