define the term specific heat capacity of a substance and state its unit​

Answers

Answer 1

Answer:

Hope this help

Explanation:

Specific heat capacity,c of a substance is the quantity of heat needed to raise the temperature of 1 kg mass of the substance by 1°C

Unit for c is J/kg/°C or J/kg/K


Related Questions

HEY CAN ANYONE PLS ANSWER DIS!!!!

Answers

Answer:

A)  distillation.

Explanation:

Benzene boils at 81∘C while chloroform at about 61∘C. The separation can be done by distillation.

please mark me brainliest! hope this helps, god bless :)

While Juliet was watching Romeo ran at a speed of 3.3 m/s straight off the end of a diving board
that is 3 m above the water. How long was he airborne before he hit the water?

Answers

s = 1/2 g t^2
t = square root ( 6/9.8) = 0.78 seconds

Is density independent of sample size?

Answers

Answer:

➢ Length, Width, Height, Volume, Mass. ➢ A size independent property is a physical property that does not change when the size of an object changes.

Examples:

➢ Examples of size independent properties: ➢ Density, Color, State of Matter.

Hope this helps :)

Student is attempting to hit a target 4 meters from the edge of the desk that is 1.4 m tall marble rules of a table horizontally as shown below according to the above information in diagram what velocity must a marble have to strike the target?

Answers

Answer:

The correct option is;

7.49 m/s

Explanation:

The time it takes the marble to fall vertically is given by the equation

s = u·t + 1/2·g·t²

Where;

s = The height of the table = 1.4 m

u = The initial vertical velocity = 0 (The marble is given only an initial horizontal push (velocity))

g = The acceleration due to gravity = 9.81 m/s²

t = The time it takes the marble to reach the ground 1.4 m below

Plugging in the values. gives;

1.4 = 0×t + 1/2 × 9.81 × t²

∴ t² = 1.4/(1/2 × 9.81) ≈ 0.28542 s²

t = √0.28542 ≈ 0.5342s

The horizontal range the marble is to cover in the approximately 1.87 seconds before it reaches the ground = 4 meters

Therefore, the velocity that allows the marble to reach 4 meters in 1.87 seconds is give as follows;

Velocity = Distance/Time = 4 m/(0.5342 s) ≈ 7.49 m/s

Therefore the horizontal velocity the marble must have to strike its target is approximately 7.49 m/s.

Two football players have a head-on collision and grab onto each other's uniforms. The 80
kg Pennridge Ram was moving at 3 m/s, while the 70 kg Souderton player was moving in
the opposite direction at 2.5 m/s. What is their final velocity after impact?

Answers

You need to calculate the momentum of each. 80x3 = 240 Kg m/s and 70x2.5 = 175 kg m/s

A ball is shot horizontally at 17.3m/s from the roof of a building 55.2 m tall, (use g = 9.8 m/s ^ 2) How far from the base of the building does the ball land?

Answers

Given that,

The initial speed of a ball, u = 17.3 m/s

It is shot from the roof of a 52 m tall building, h = 52 m

It is required to find the distance from the base of the building the ball land. Let the distance be d.

Final velocity of the ball, v = 0 (when it lands)

We can use third equation of motion to find it.

[tex]v^2-u^2=2ad[/tex]

a = -g

[tex]-u^2=-2gd\\\\d=\dfrac{u^2}{2g}\\\\d=\dfrac{(17.3)^2}{2\times 9.8}\\\\d=15.26\ m[/tex]

So, it will land at a distance of 15.26 m.

i need help with #3 plz and thank you

Answers

Number 1 the correct answer

A student lifts a school bag from the ground and puts it on his shoulders 1.5m above the ground. A force of 5N is acting on an object. Calculate the work done by him on the school bag.

Answers

Answer:

w = 7.5 [J]

Explanation:

We must remember the definition of mechanical work, which tells us that work is equal to the product of force by distance. This force must be applied in the direction of movement. So we have the following equation:

w = F*d

where:

w = work [J]

F = force [N]

d = distance [m]

Now replacing we have:

w = 5*1.5

w = 7.5 [J]

Why are ions formed?
Group of answer choices

A.Because atoms have the same number of protons and electrons

B. Because atoms want 8 valence electrons

C. To make our lives difficult

D. Because atoms gained neutrons

Answers

Answer:

B. Because atoms want 8 valence electrons

Explanation:

Ions are formed because atoms want 8 valence electrons. Most atoms attain stability when they 8 electrons in their outermost shell.

This is the reason why they form ions.

To form ions, atoms will gain or lose electrons or share them. This loss, gain, or sharing of electrons often lead to an atom become stable. One group of atoms, the noble gases, do not form ions readilyThey have complete numbers of electrons in their valence shells. So they do not gain, lose or share their electrons to form ions unlike the others.

A biker starts moving from rest with a constant acceleration of 2.0 m/s^2. What is his velocity after 5.0 s?

Answers

a = v-u/t

2 = v - 0 / 5

2 = v/5

v = 10 m /s

Acar accelerates from 5 ms to 27 mis in 10 seconds. What is the acceleration in m/s??

Answers

Explanation:

Acceleration is final velocity minus initial velocity divided by time.

a = (v − u) / t

a = (27 m/s − 5 m/s) / 10 s

a = 2.2 m/s²

NEED HELP ASAP PLS (with work)
A punt is kicked at an angle of 60 with a speed of 40 m/s, and lands at the same
height from which it was kicked.

How far away will the ball land?

What is the maximum height reached by the ball?

What is the hang time? Total

Answers

Answer:

1) The ball will land approximately 141.4 m away from where it was kicked

2) The maximum height reached is approximately 61.22 m

3) The total hang time is approximately 7.07 seconds

Explanation:

First we list out the known parameters

The direction in which the punt is kicked, θ = 60°

The speed with which the punk is kicked, v₀ = 40 m/s

1) The distance away (the range, R) the ball will land is given by the equation;

[tex]R = \dfrac{v_0^2 \times sin(2\cdot \theta)}{g}[/tex]

Where;

g =  The acceleration due to gravity = 9.8 m/s²

Substituting the values, gives;

[tex]R = \dfrac{40^2 \times sin(2\times60^{\circ })}{9.8} \approx 141.4 \ m[/tex]

The distance away the ball will land ≈ 141.4 m

2) The maximum height is given m=by the following equation for vertical motion;

(v₀ × sin(θ))² = 2 × g × [tex]h_{max}[/tex]

Obtained from the equation of motion, v² = u² - 2×g×h where at maximum height;

v = 0 at maximum height, the ball stops upward motion

h = Height of motion = [tex]h_{max}[/tex] at maximum height

v, and u are the vertical component of the velocity, v₀

Substituting the values in the equation for the maximum height, gives;

(40 × sin(60))² = 2 × 9.8 × [tex]h_{max}[/tex]

(40 × (√3)/2)² = 1200 = 19.6 × [tex]h_{max}[/tex]

1200 = 19.6 × [tex]h_{max}[/tex]

[tex]h_{max}[/tex] = 1200/19.6 ≈ 61.22 m

The maximum height reached ≈ 61.22 m

3) The time to maximum height is given by the following equation of motion;

[tex]v_y[/tex] = v₀ × sin(θ) - g × t

[tex]v_y[/tex] = 0 at maximum height

We therefore have;

v₀ × sin(θ) = g × t

t =  v₀ × sin(θ)/g = 40 × sin(60°)/9.8 = (40 ×(√3)/2)/9.8 = 3.535 seconds

Given that the motion of the ball is symmetrical about the maximum height, we have;

The time from ground level to maximum height = The time from the maximum height back to the ground level

The total time hang time = The time from ground level to maximum height + The time from the maximum height back to the ground level

The total time hang time ≈ 3.535 + 3.535 ≈ 7.07 seconds.

The total time hang time ≈ 7.07 seconds.

Bella kicks a soccer ball due north with 80.0 N of force. The acceleration is 195 m/s2. What is the mass of the soccer ball?

Answers

Force = mass × acceleration

80 = M × 195

M = 80/195

M ≈ 0,4 kilograms

Answer:

F=ma

a=F/m

so kickball having less mass will result to more acceleration

Explanation: i said so andddd when i put this it said it was right hehe

the energy lost between trophic levels why?

Answers

Answer:

Explanation:

Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level. Trophic level transfer efficiency (TLTE) measures the amount of energy that is transferred between trophic levels

Sarah is asked to sort out the list of ions and ionic compounds. How can Sarah differentiate between the ions and ionic compounds? Ions have a positive or negative charge, but an ionic compound's overall charge is zero. Ions have no charge, but ionic compounds have a positive charge. Ions have no charge, but ionic compounds have a negative charge. Ions have a positive or negative charge, but an ionic compound's overall charge is negative.

Answers

Answer:

Ions have a positive or negative charge, but an ionic compound's overall charge is zero.

Explanation:

Ionic compounds are compounds said to contain ions, which are atoms that have either lost electrons to be POSITIVELY CHARGED or gained electrons to be NEGATIVELY CHARGED. The negatively charged ions are called ANIONS while the positively charged ions are called CATIONS.

These cations (+ ions) and anions (- ions) make up ionic compounds in such a way that they give the ionic compound a net charge of ZERO. This is because the charges of the opposite ions that make up the ionic conpound are equal. For example, in the ionic compound CaCl2;

Ca is a cation with charge +2

Cl is an anion with charge -1, 2 atoms make a net charge of -2

When these two ions combine, they cancel out each other to form an ionic compound, CaCl2, with net charge 0 or neutral

Answer:

The answer is

A. Ions have a positive or negative charge, but an ionic compound's overall charge is zero

i got it right on edge 2023

good luck

An alien spaceship is 300 m above the ground and moving at a constant velocity of 250 m/s upwards. How high above the ground is the ship after 3 seconds?

Answers

Answer: 1050 m

Explanation: 300 + 250x3 = 1050.

Which two options are forms of kinetic energy?
A. Nuclear energy
B. Thermal energy
C. Chemical energy
D. Gravitational energy
E. Sound energy

Answers

Answer:

B. Thermal energy

E. Sound energy

Explanation:

Thermal and sound energy is kinetic energy.

Kinetic energy is the energy that results as a function of the motion of a body or the particles of the medium.

Sound energy is transmitted by the vibration of the particles in the air. The vibration leads to movement of the particles and hence, kinetic energy is produced.

Thermal energy originates as a result of the temperature differences in a body. This temperature difference leads to the increase in the kinetic energy of some particles which also causes vibration and motion of the particles.

The two options which are forms of kinetic energy include:

Thermal energySound energy

What is Kinetic energy?

Kinetic energy is the form of energy possessed by a body by virtue of its

motion.

Thermal energy possesses kinetic energy as a result of the high

temperature bringing about an increase in the collision of the particles.

Sound energy also possesses kinetic energy as a result of the vibrations

through the movement of energy in a medium.

Read more about Kinetic energy here https://brainly.com/question/8101588

HEY CAN ANYONE PLS ANSWER DIS!!!!!!

Answers

Answer:

Explanation:

1.wrap bar magnet in a plastic baggie and remove the iron filings from the mixture by using a bar magnet. Place a small piece of scrap paper on the scale and “tare” the scale. Then place filings on the scrap paper and record (e) the mass of the iron filings. Don't throw out the iron–save it to be recollected.

2.When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation.

3.Sand (mostly silicon dioxide) is not.

Pour the salt and sand mixture into a pan.

Add water. ...

Heat the water until the salt dissolves. ...

Remove the pan from heat and allow it to cool until it's safe to handle.

Pour the salt water into a separate container.

Now collect the sand.

Pour the salt water back into the empty pan.

Heat the salt water until the water boils. Continue boiling it until the water is gone and you're left with the salt.

Another way you can separate the salt water and sand is to stir up the sand/salt water and pour it through a coffee filter to capture the sand.

Answer:

1. Separating iron from mixture

Provided a magnetmoved the magnet close to the mixtureseparated the magneted iron from the magnet.

2. Separating sand from mixture

poured the mixture in a separation funnelfiltered off the sand from the mixture.

3. Separating Salt mixture

boild the mixturecontinued heating to drynessthe remimants left behind is the salt

When are island-arc volcanoes formed?

Answers

Answer:

Its the result from subduction of an oceanic tectonic plate when its under another tectonic plate. Sometimes parallel the oceanic trench. Also if a volcano is offshore, it forms islands, which will result in a volcanic type of island arc.

Explanation:

Hope this helps! If this wasn't the answer you were looking for, please don't hesitate to comment here or private message me. Also if you have any other questions concerning something you don't know or want to learn about, also private message me or comment here! Have a nice day/night!! :))

What is a non-example of Newton's 3rd law of motion?

Answers

Answer:

Unbalanced forces are not examples of Newton's third law because not all opposite reactions are unbalanced forces.

Explanation:

HELP ASAP! Will make BRAINLEST
Which two options are reasons that electromagnetic waves can be used effectively in communication devices?

A. The speed at which they carry information can be varied.
B. They require no wires to carry information
C. Any type of electromagnetic wave can be used for communication.
D. They can travel through either air or other types of matter.​

Answers

Answer:

B and D

Explanation:

Did the quiz

Electromagnetic waves require no wires to carry information and can travel through either air or other types of matter.​ Therefore, options (B) and (D) are correct.

What are electromagnetic waves?

Electromagnetic radiations are produced when an electric field comes in contact with the magnetic field. Electromagnetic waves are the composition of oscillating electric as well as magnetic fields.

Infrared radiation is used in security cameras and used for night vision. UV rays are useful to detect forged banknotes as the real banknotes don’t turn fluorescent under UV light.

Electromagnetic radiation can travel energy in a vacuum or air. Electromagnetic waves play a vital role in today's communication technology. Electromagnetic waves are specially used in RADARS to detect aircraft in the earth's atmosphere.

Radio waves, microwaves, infrared (IR), and visible light can be used for communication. Radio waves are used to transmit information on television and radio programs. Microwaves are used to transmit satellites, mobile phones, and television.

Learn more about the electromagnetic wave, here:

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What is the mass number of a carbon atom which has six protons and
six neutrons.

Answers

Answer:

The mass number of carbon atom is 6+6=12

The drawing shows a 26.1-kg crate that is initially at rest. Note that the view is one looking down on the top of the crate. Two forces, and , are applied to the crate, and it begins to move. The coefficient of kinetic friction between the crate and the floor is k = 0.347. Determine the (a) magnitude and (b) direction (relative to the x axis) of the acceleration of the crate.

Answers

Answer:

(a). The magnitude of the acceleration of the crate is 1.44 m/s².

(b). The direction  of the crate is 34.60°.

Explanation:

Given that,

Mass of crate = 26.1 kg

Coefficient of kinetic friction = 0.347

We need to calculate the resultant force

Using figure

[tex]F'=\sqrt{(F_{x}+F_{z})^2+F_{y}^2}[/tex]

Put the value into the formula

[tex]F'=\sqrt{(88\cos{55}+54)^2+(88\sin 54)^2}[/tex]

[tex]F'=126.4\ N[/tex]

(a). We need to calculate the acceleration of the crate

Using formula of sum of force

[tex]\sum{F}=F'-\mu N[/tex]

[tex]ma_{total}=F'-\mu mg[/tex]

[tex]a_{total}=\dfrac{F'}{m}-\mu g[/tex]

Put the value into thr formula

[tex]a_{total}=\dfrac{126.4}{26.1}-0.347\times9.8[/tex]

[tex]a_{total}=1.44\ m/s^2[/tex]

(b). We need to calculate the direction

Using formula of the direction

[tex]\theta=\tan^{-1}(\dfrac{F_{y}}{F_{x}+F_{z}})[/tex]

Put the value into the formula

[tex]\theta=\tan^{-1}(\dfrac{88\sin55}{88\cos55+54})[/tex]

[tex]\theta=34.60^{\circ}[/tex]

Hence, (a). The magnitude of the acceleration of the crate is 1.44 m/s².

The direction  of the crate is 34.60°.

Why is thermal energy classified as kinetic energy?

Answers

Answer:

Thermal energy is an example of kinetic energy, as it is due to the motion of particles, with motion being the key. Thermal energy results in an object or a system having a temperature that can be measured. Thermal energy can be transferred from one object or system to another in the form of heat.

Explanation:

Answer:

Thermal energy is an example of kinetic energy, as it is due to the motion of particles, with motion being the key. Thermal energy results in an object or a system having a temperature that can be measured. Thermal energy can be transferred from one object or system to another in the form of heat.

Explanation:

what is the skydivers acceleration

Answers

I can’t see the photo:(
is it in mph you are welcome

Someone help please.....
A person jogs 4.0 km in 32 minutes, then 2.0 km in 22 minutes, and finally 1.0 km in 16 minutes. What is the jogger's average speed in km per minute?​

Answers

Answer:

0.0928km/min (4dp)

Explanation:

To find the jogger's speed in km per minute, we just need to divide the number of km jogged by the time in minutes it took to jog that distance. This will give us the distance they jogged every minute which is their speed.

4km in 32 minutes:

4/32 = 0.125km/min

2km in 22 minutes:

2/22 = 0.091 (3dp)km/min

1km in 16 minutes:

0.0625km/min

Now to find the average speed of these 3 speeds, we just add them all together and divide by how many values there are (3 values).

Average (mean)  = [tex]\frac{0.125+0.091+0.0625}{3}[/tex]

Average = 0.2785/3

Average speed of jogger = 0.0928 (4dp) km/min

Hope this helped!

What is the displacement of a soccer player who moves from 20 yards to 65 yards down the field?

Answers

Answer:

All that is necessary is that car A has a greater speed (is moving faster). ... A fullback is running down the football field in a straight line. ... At 1 second, he is on the 10-yard line; at 2 seconds, he is on the 20-yard line; at 3 seconds, he is on ... Since average velocity is displacement over time, his average velocity is also 0 m/s.

Explanation:

Answer:

45 yards of displacement from the 20 yard point

Explanation:

take the 65 and subtract 20 from it and that will give you your displacement.

How does the earthquake magnitude work

Answers

Answer:

The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included in the magnitude formula to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquakes.

Explanation:

have a good day

Give two examples of energy being transformed from one type to another

Answers

Answer:

Explanation:

For example, an ice cube has heat energy and so does a glass of lemonade. If you put the ice in the lemonade, the lemonade (which is warmer) will transfer some of its heat energy to the ice.

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m​

Answers

19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m19. Calculate the work done when a 30 N force pushes a rock 10 m. a) 3J b) 0.33 J c) 40 J d) 300 J

20. How far did a rock move if a force of 200 N moved it doing 100 J of work? a) 2 m b) 0.5 m c) 20,000 m d) 300 m

21. An explosion of gas from a Hawaiian volcano blows a rock into the sky. the rock has 2000J of kinetic energy. What was its mass if the rock had a velocity of 20m/s. a) 200Kg b) 20,000Kg c) 10Kg d) 200Kg

22. How much potential energy does a 2 kg book have if it is 2 meters from the ground? a) 39.2J b) 12 J c) 19.6 J d) 98 J

23. 45J of work were done on the object that moved 5M. How much force was applied to the object? a) 8N b) 9N c) 225N d) ON

24. If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to. a) 400m b) 50m c) 40m d) 4m

25. A force of 100 newtons was necessary to lift a rock. A total of 150 joules of work was done. How far was the rock lifted? a) 1.5 m b) 15 m c) 0.15 m d) 150 m

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Other Questions
The Sheridan Inc., a manufacturer of low-sugar, low-sodium, low-cholesterol TV dinners, would like to increase its market share in the Sunbelt. In order to do so, Sheridan has decided to locate a new factory in the Panama City area. Sheridan will either buy or lease a site depending upon which is more advantageous. The site location committee has narrowed down the available sites to the following three very similar buildings that will meet their needs. Building A: Purchase for a cash price of $612,100, useful life 26 years. Building B: Lease for 26 years with annual lease payments of $71,490 being made at the beginning of the year. Building C: Purchase for $655,200 cash. This building is larger than needed; however, the excess space can be sublet for 26 years at a net annual rental of $6,850. Rental payments will be received at the end of each year. The Sheridan Inc. has no aversion to being a landlord. In which building would you recommend that The Sheridan Inc. locate, assuming a 11% cost of funds? Quakers were most likely to live in which colonial region of the British colonies inNorth America? Someone please help me with this. Btw this is 6th grade math REFLECT - How many triangles and how many rectangles are in a net for a right triangularprism? How do you know? STORIES OF USEFUL INVENTIONS, excerptBy S. E. Forman1911THE MATCHThere never was a time when the world was without fire, but there was a time when men did not know how to kindle fire; and after they learned how to kindle one, it was a long, long time before they learned how to kindle one easily. In these days we can kindle a fire without any trouble, because we can easily get a match; but we must remember that the match is one of the most wonderful things in the world, and that it took men thousands of years to learn how to make one. Let us learn the history of this familiar little object, the match.Fire was first given to man by nature itself. When a forest is set on fire by cinders from a neighboring volcano, or when a tree is set ablaze by a thunderbolt, we may say that nature strikes a match. In the early history of the world, nature had to kindle all the fires, for man by his own effort was unable to produce a spark. The first method, then, of getting fire for use was to light sticks of wood at a flame kindled by natureby a volcano, perhaps, or by a stroke of lightning. These firebrands were carried to the home and used in kindling the fires there. The fire secured in this way was carefully guarded and was kept burning as long as possible. But the flame, however faithfully watched, would sometimes be extinguished. A sudden gust of wind or a sudden shower would put it out. Then a new firebrand would have to be secured, and this often meant a long journey and a deal of trouble.In 1827, John Walker, a druggist in a small English town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. The druggist had discovered the first friction-chemical match, the kind we use to-day. It is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. Although Walker's match did not require the bottle of acid, nevertheless it was not a good one. It could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. In a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. The match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. It would ignite when rubbed on any dry surface, and there was no longer any sputtering. This was the phosphorus match, the match with which we are so familiar.Read the first sentence of the text:There never was a time when the world was without fire, but there was a time when men did not know how to kindle fire; and after they learned how to kindle one, it was a long, long time before they learned how to kindle one easily.What is the main purpose of this sentence in the essay? To describe the misery of early human existence To explain how early fires were started To suggest humans have an easier life than we once did To support the idea that matches really changed human life find the measure of angle J .will mark brainiest h(x) = 3x-4 g(x) = x + 3+ x Find h(n-2)+ g(n-2) Fill in the blank with the word that best completes the sentence.Les bananes sont __________que les brocolis.mieuxmeilleuremeilleurmeilleuresIF YOU ARE GOOD AT FRENCH, please head over to my profile and look at the questions- and answer questions starting from the one marked 14)best answers get marked 'brainliest'Thank you! HELP HELP HELP Why do minerals look the way they do Reread this excerpt from The Call of the Wild.An oath from Perrault, the resounding impact of a club upon a bony frame, and a shrill yelp of pain, heralded the breaking forth of pandemonium. The camp was suddenly discovered to be alive with skulking furry forms,starving huskies, four or five score of them, who had scented the camp from some Indian village. They had crept in while Buck and Spitz were fighting, and when the two men sprang among them with stout clubs they showed their teeth and fought back. They were crazed by the smell of the food. Perrault found one with head buried in the grub-box.What is the meaning of this excerpt?A. Perrault is fighting stray dogs that have invaded the campsite looking for food.B. Perrault is punishing members of his dogsled team for their aggressive acts.C. Perrault is reprimanding his dogsled team for stealing scraps of food.D. Perrault is feeding wild dogs and training them for work on his team. if a rock is soft and the color blue is red then my is a car driving a fish then why are my shoes untied? PLEASE HELP WITH THIS LAST ONE ASAP!!!!!!!!! A circular crop field has an irrigation system in which a pipe, with one end attached to a tower at the center of the field, turns continuously to deliver water. The horizontal distance, in meters, from the tip of the pipe to the farmhouse is represented by y = Equals 400 sine (StartFraction pi Over 8 EndFraction x + pi) + 500, where x represents time in hours.What does the amplitude of this function represent?A.the length of the pipeB.the distance between the tower and the farmhouseC.the time it takes for the pipe to complete one full circleD.the difference between the maximum and minimum distances from the tip of the pipe to the farmhouse conflict mean:A)Difference of opinin.B)Medical prognosis.C)Chance event.D)Ocean trip. Find the polynomial function of degree 3 such that f(2)=24 and x-1, x and x+2 are factors of the polynomial What are the relationships between the different wave properties (frequency, wavelength, wave speed, period, amplitude)Ex) As ___ increases, ___ increases/decreases/remains the same. Summary of silent spring does anyone know how to do the alien periodic table im stuck and cant go furhter I need help with this math problem plz help What is a result of a mixture?