what was a luxury but is now considered a necessity.

Answers

Answer 1

Answer:

a cellphone

Explanation:

pls mark brainliest

Answer 2

Answer:

A car

Explanation:


Related Questions

Please have a look at the image

Answers

Answer:

a

Explanation:

a. zero is the answer...

Question attached i need answers quick

Answers

1 P4 + 3 O2 —> 1 P4O6

Using the diagram below, calculate the PE and KE of the ball at the top, middle, and bottom of a drop. SHOW YOUR WORK!!

Write an explanation of what would happen to the ME, PE, and KE of the ball from the top of the drop to the middle of the drop, and then at the bottom.

Answers

Answer:

At the top

K.E = 0

P.E = 981 J

Mechanical energy is conserved

P.E is maximum

K.E = 0

At the middle

K.E = 981 J

P.E = 0

Mechanical energy is conserved

K.E is maximum

P.E = 0

At the bottom

K.E = 0

P.E = 981 J

Mechanical energy is conserved

K.E = 0

P.E is maximum

Explanation:

Given that

M= 5kg

H = 20 m

t = 7 s

According to conservation of energy,

At the top

K.E = 0

P.E = mgh

P.E = 5 × 9.81 × 20

P.E = 981 J

Mechanical energy is conserved

P.E is maximum

K.E = 0

At the middle

K.E = 981 J

P.E = 0

Mechanical energy is conserved

K.E is maximum

P.E = 0

At the bottom

K.E = 0

P.E = 981 J

Mechanical energy is conserved

K.E = 0

P.E is maximum

Given that

M= 5kg

H = 20 m

t = 7 s

At the top

K.E = 0

P.E = mgh

P.E = 5 × 9.81 × 20

P.E = 981 J

Mechanical energy is conserved

P.E is maximum

K.E = 0

At the middle

K.E = 981 J

P.E = 0

Mechanical energy is conserved

K.E is maximum

P.E = 0

At the bottom

K.E = 0

P.E = 981 J

Mechanical energy is conserved

K.E = 0

P.E is maximum

Explanation:

Given that

M= 5kg

H = 20 m

t = 7 s

At the top

K.E = 0

P.E = mgh

P.E = 5 × 9.81 × 20

P.E = 981 J

Mechanical energy is conserved

P.E is maximum

K.E = 0

At the middle

K.E = 981 J

P.E = 0

Mechanical energy is conserved

K.E is maximum

P.E = 0

At the bottom

K.E = 0

P.E = 981 J

Mechanical energy is conserved

K.E = 0

P.E is maximum

Plz Help! Will give brainliest!!
If the work output of a simple machine is 40 J and the work input is 50 J, the percent efficiency is _____%.
A. 5/4
B. 10
C. 80
D. 90​

Answers

Answer: 80%

Explanation:

Answer:

C.80

Explanation:

What is the resistance of a 6.0 m long gold wire (ρgold = 5.6 x 10 -8 Ω-m) whose cross-sectional area is 5x10 -7m 2 ? (Please show some work)

Answers

Answer:

R =0.672 ohms

Explanation:

We have,

Length of a gold wire is 6 m

Resistivity of gold is [tex]5.6\times 10^{-8}\ \Omega-m[/tex]

Area of cross section of the wire is [tex]5\times 10^{-7}\ m^2[/tex]

The resistance of a wire is given by the relation as follows :

[tex]R=\rho\dfrac{l}{A}\\\\R=5.6\times 10^{-8}\times \dfrac{6}{5\times 10^{-7}}\\\\R=0.672\ \Omega[/tex]

So, the resistance of the gold wire is 0.672 ohms.

Which of the following is a homogenous mixture?

Answers

Answer:

Blood

Explanation:

Homogenous means the same type and a box with toys, spaghetti and meatballs, and trail mix all have variety.

Answer:

B is the correct answer

In a science experiment showing the splitting of water into Oxygen and hydrogen, two inverted test tubes of water were placed over the site of the reaction. (see the pic) How can you tell which one was catching the oxygen and which one was catching the hydrogen? Question 4 options: The hydrogen is a positive ion and will be located close to the negative terminal of the battery. The oxygen is a negative ion which will be located next to the negative terminal of the battery. There are 2 hydrogen atoms for every oxygen atom. The hydrogen will take up more space and is pushing the water lower in the test tube. The hydrogen, being a smaller atom, will take up less space than the oxygen. It will push the water down less.

Answers

Answer:

There are 2 hydrogen atoms for every oxygen atom. The hydrogen will take up more space and is pushing the water lower in the test tube.

Explanation:

To find out what water is made of, we may have to look at its chemical formula, which is H2O. This basically tells us that the water molecule is composed of two elements: hydrogen and oxygen or, more precisely, two hydrogen atoms (H2) and one oxygen atom (O). Hydrogen and oxygen are gases at room temperature. Splitting water into its two components is much easier to do by a process called water electrolysis. Making hydrogen or oxygen this way seems simple. In water electrolysis, the source of energy used is electricity. An easy way to generate electricity is with a battery. Because pure water is not good at conducting electricity, however, electrolysis requires the addition of an electrolyte, such as salt or acid. The electrolyte dissolves in water and separates into ions (electrically charged particles) that move through the solutions and are able to conduct electricity this way.

As electrolysis progresses, the water level at the negative terminal becomes about half that of the positive terminal, meaning that we have collected double the amount of hydrogen gas compared with oxygen. The difference is due to the fact that one water molecule has two hydrogen atoms to one oxygen atom, as explained above. This means it takes two water molecules (2 H2O) to make one oxygen molecule (O2). At the same time, however, two molecules of water (2 H2O) can make two molecules of hydrogen (2 H2). Hence the answer.

Two identical speakers are 3.50 m and 5.20 m from a listener. What is the lowest frequency (n = 1) that would cause constructive interference there? PLS HELP!

Answers

For constructive interference the path difference must be an integer number of wavelengths. The lowest frequency for this would be the longest wavelength with the path difference equal to one wavelength.

Path length difference(m) = 5.20 - 3.50 = 1.70m.

λ =2m ⇒ f = v/λ

λ/2 =1.70

λ = 3.40m

Taking speed of sound as v = 340m/s:

f = v/λ = 340/3.40 = 100Hz.

What is constructive interference?

"When two waves of identical wavelength are in phase, they form a new wave with an amplitude equal to the sum of their individual amplitudes."

Know more about constructive interference here

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Answer:114

Explanation:

for Acellus

At t = 0, a car has a speed of 30.0 m/s. At t=6.00 s, its velocity is 12.0 m/s.
What is its average acceleration during this interval? plz help...​

Answers

Answer: [tex]-3m/s[/tex]

Explanation:

[tex]a=\frac{V_2-V_1}{t}[/tex]

[tex]a=\frac{12-30m}{6s}\\a=-\frac{18m}{6s}\\ a=-3m/s[/tex]

We have a negative acceleration, meaning that the car is slowing down.

Which is a true statement?


A.
Valence electrons play a key role in chemical reactions.


B.
The properties of elements in a group are identical.


C.
Hydrogen contains multiple valence electrons.

Answers

Answer:

C

Explanation:

A wave that is traveling toward an interface is called the...??

Answers

Answer:

Surface wave

Eg ocean wave

Surface wave. Is the answer

In terms of forces, what makes the arrow start moving?

Answers

Answer:

the answer is A force is a push or pull that changes the motion of an object. Forces can make objects start or stop moving, cause objects that are already moving to speed up or slow down, or make objects change direction. Force arrows are used to represent both the magnitude and direction of forces.

Explanation:

hope this helps u stay safe

A Physics question regarding circuits and electricity.

Answers

Assuming all three bulbs are connected properly with their conductivity creating a circuit, if one is unscrewed all bulbs would shut off causing zero emission of light to be displaced. Meaning answer D would be the closest to the right response.

Hope this helps! :)

PLEASE ANSWER ASAP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answers

Answer: I believe the answer is B (the second option)

side note: this shows a physics question . . . it is not

An acrobat performs with a swing, as shown in the diagram . Which of these most likely happens as the acrobat moves from Point 1 to Point 2?

A. Potential energy decreased and kinetic energy increases.
B. Potential energy increases and kinetic energy decreases.
C. Both potential and kinetic energy increase.
D. Both potential and kinetic energy decrease.

Even on a windy day, most plants can remain upright. Which structure plays the greatest role in providing a plant with this type of support?
A. nucleus
B. mitochondrion
C. cell wall
D. skeleton

Which BEST describes one way igneous rocks form?
A. Sedimentary rocks erode.
B. Sedimentary rocks are compacted.
C. Metamorphic rocks are melted, then cooled.
D. Metamorphic rocks are deposited and cemented.
Pls help! will give brainliest and 75 Points for the correct answers!

Answers

Acrobat part
A
Plants
b
Rocks
C

Answer:

Well, The first question is C. Both potential and kinetic energy increase. Then, The second question is C. Cell wall. And, The last one is B. Sedimentary rocks ate compacted. Good Luck!

During which two phases would surfer’s most likely benefit

A. New and Full Moon
B. New moon and Waxing Crescent
C. Full Moon and Waxing Gibbous
D. 1st Quarter and 3rd Quarter

Answers

D. Because there is little tidal change

The phases where surfer’s most likely benefit include D. 1st Quarter and 3rd Quarter.

Surfers will benefit include during the 1st Quarter and 3rd Quarter because there's tidal change. Tidal change is when coastal areas experience two low and high tides.

The benefit of surfing during this period is that it helps jack the waves. Waves transmit energy and this is important to surfers.

Read related link on:

https://brainly.com/question/18253248

What does the term “retroperitoneal” mean in the terms of the location of the kidneys ?

Answers

Answer:

"Retroperitoneal" refers to the back of the peritoneum, the membrane that lines the anatomical space in the abdominal cavity. Kidney stones may cause pain to the organs within the retroperitoneal space. A diagram of the aorta, a retroperitoneal structure.

Explanation:

A book with a mass of 1.2 kg sits on a bookshelf. If it has gravitational potential energy of 50 j, how high is the shelf ? The acceleration of gravity is 9.8 m/s 2

Answers

Answer:

B

Explanation:

The shelf will be b) 4.3 m high

What is Gravitational potential energy ?

Gravitational potential energy is the energy possessed or acquired by an object due to a change in its position when it is present in a gravitational field.

given

mass = 1.2 kg

gravitation potential energy = 50J

h = ?

acceleration of gravity is 9.8 m/s 2

gravitation potential energy  = m*g*h

50 J = 1.2 kg * 9.8 m/s^2  * h

h= 4.251 m

h ≈ 4.3 m

The shelf will be b) 4.3 m high

learn more about gravitation potential energy  :

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The burning of fossil fuels contributes to the addition of greenhouse gases to the atmosphere. These gases trap thermal energy in the Earth’s atmosphere. Which of the following would be the most reasonable changes that could result from an increase in the burning of fossil fuels?
A. The air all over the globe would become dirtier.

B. There would be a global rise in temperatures.

C. Ecosystems would become more diverse.

D. Rates of photosynthesis would decrease.

Answers

Answer:

B. there would be a global rise in temperatures

Hence, global warming

Explanation:

hope this helped! :D

Hey there!

The answer would be B. There would be a global rise in temperatures.

If fossil fuels contribute to the addition of greenhouse gases to the atmosphere and these same gases increase because of burning fossil fuels then there would be a global rise in temperatures. Which is answer B.

Hope this helps!

if 34.7 g of O2 reacts with iron to form 79.34 g of iron oxide, how much iron was used in the reaction?

A.
19.84 g

B.
44.64 g

C.
104.1 g

D.
114.04 g

Answers

Answer: B. 44.64 g

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

Mass of reactants = mass of iron + mass of oxygen = mass of iron + 34.7 g

Mass of product = mass of iron oxide = 79.34 g

As Mass of reactants = Mass of product

mass of iron + 34.7 g = 79.34 g

mass of iron = 44.64 g

Thus 44.64 g of iron was used in the reaction

In a 200 meter sprint there is one curve and one straightaway? true or false

Answers

Answer:

I got true

Explanation:

Not the best explanation, but my dad said it was true.

PLS I NEED THIS QUICK!!!!WILL GIVE BRAINLY!
you decide to push on a brick wall with all your might for 5 minutes. you push so hard that you begin to sweat. however, the wall does not move. if you end up pushing with a force of 500 newtons, how much work did you do?

Answers

Answer:

2500

Explanation:

What do snow melting, water freezing to ice, and water boiling into steam have in
common? *
O
They involve a change in state.
They involve a change in temperature.
O
They involve a change in thermal energy.
All of the above are true.​

Answers

Answer:

All of the above.

Explanation:

All of the above is the answer!

motives are activated by

A) thoughts.
B) internal physiological states.
C) external cues.
D) all of these

Answers

Answer:

D all of these gufjbihbuxhbi

Can someone please answer these two science questions. Please don't answer with just anything for the points, I genuinely need the answers. Thanks! :)

Answers

6.

Answer:

45 meters

Explanation:

notice that is you multiply the time with the speed the units cancel to get distance.

therefore

distance=velocity(time)

distance=(3)15

distance =45 meters

7.

Answer:

1. the speed is constant

2. the average speed is .5 m/s

Explanation:

I have attached a graph of the data in excel.

from excel i got the equation of the line to be y=.5x with y being distance and x being time.

the function is a position function so if you take the derivative of it you get the velocity which is .5.

since the derivative is a constant the the speed does not change and the average velocity is the derivative.

Which angle is the angle of refraction?

1
2
3

Answers

The angle of refraction is 3

The correct option is 3.

What is the angle of incidence and refraction?

The angle formed at the point of incidence between the incident ray and the normal is called the angle of incidence. The angle formed between the refracted ray and the normal is called the angle of refraction. The angle of Incidence and Angle of Refraction.

What is N in Snell's law?

As in reflection, we measure the angles from the normal to the surface, at the point of contact. The constants n are the indices of refraction for the corresponding media.

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You are a traffic accident investigator. You have arrived at the scene of an accident. Two cars of equal mass (1,000 kg each) were involved in a rear-end accident at a stop sign. Here is what you know: Car 1 approached the intersection from the top of a 25-meter hill. Car 2 was on a flat stretch of road directly in front of Car 1. At the bottom of the hill, Car 1 was going 20 m/s; Car 2 was going 30 m/s before it stopped at the stop sign. There were no skid marks left by Car 2. The collision occurred at the stop sign, where Car 2 had stopped. After the collision, both cars were moving together in the same direction at 10 m/s before slowly rolling to a stop. You must now push Car 2, using 800 N of force, 10 meters off to the side of the road so no one else gets hurt.
1. What was the potential energy of Car 1 at the top of the hill? (3 points)




2. What was the kinetic energy of each car before braking? (4 points)




3. A. How much energy did Car 1 lose from the top to the bottom of the hill? (3 points)




B. Where do you suppose that energy went? (2 points)




4. How much work was done to bring Car 2 to a stop? (4 points)




5. If Car 2 came to a stop in 15 seconds, how much power (in watts) did it take to stop Car 2 at the stop sign by applying force to the brakes? (3 points)




6. What is the final combined momentum of the cars right after the accident? (6 points)




7. Assuming that there are no other nonconservative forces involved, what impulse was given to each car during the collision? (6 points)
A. Car 1 (3 points)




B. Car 2 (3 points)




8. How much energy did Car 1 lose in the collision? (3 points)




9. How much energy did Car 2 gain in the collision? (3 points)




10. Which of the two laws covered in this unit - Law of Conservation of Momentum or Law of Conservation of Energy - is obeyed in this problem? Explain your reasoning. (5 points)




11. How much work did it take to move Car 2 off to the side of the road? (3 points)




12. If it took you 40 seconds to move Car 2 off the road, how much power did you expend? (3 points)




13. Which simple machine does a car have that helped you move Car 2? Explain. (2 points)

Answers

6. Is 50 m/s that’s the answer

As SCUBA divers go deeper underwater, the pressure from the weight of all the water above them increases tremendously which compresses the gases in their blood. What happens to the volume of gas in their blood as the diver rises quickly to the surface?



A.
As a diver rises, the pressure on their body decreases which allows the volume of the gas to decrease.

B.
As a diver rises, the pressure on their body increases which allows the volume of the gas to decrease.

C.
As a diver rises, the pressure on their body decreases which allows the volume of the gas to increase.

D.
As a diver rises, the pressure on their body increases which allows the volume of the gas to increase.

Answers

Answer: A.

As a diver rises, the pressure on their body decreases which allows the volume of the gas to decrease.

Explanation:

The problem is that a diver, experiences an increased pressure of water compresses nitrogen and more of it dissolves into the body. Just as there is a natural nitrogen saturation point at the surface, there are saturation points under water. Those depend on the depth, the type of body tissue involved, and also how long a diver is exposed to the extra pressure. The deeper a diver go, the more nitrogen the body absorbs.

The problem is getting rid of the nitrogen once you ascend again. As the pressure diminishes, nitrogen starts dissolving out of the tissues of the diver's body, a process called "off-gassing." That results in tiny nitrogen bubbles that then get carried to the lungs and breathed out. However, if there is too much nitrogen and/or it is released too quickly, small bubbles can combine to form larger bubbles, and those can do damage to the body, anything from minor discomforts all the way to major problems and even death.

What can happen if the excretory system doesn't work properly ?

Answers

Kidney failure may lead to permanent loss of kidney function.

Please help! I'll mark you as branliest!!! :)

Answers

Answer:

pretty sure its C, Radiation because the sun produces radiation

Explanation:

Answer: conduction

Explanation:

The sand is directly transferring heat to the people. They are touching, so it would be an example of conduction.

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