Which is an example of a chemical change?

Answers

Answer 1
Burning a log of wood is an example of a chemical change

Related Questions

An object falling from a great height in Earth's atmosphere eventually reaches a speed called Terminal velocity. What cause a falling object to stop increasing in speed once it reaches terminal velocity? Really struggling, I need an answer--quick. Which letter is correct and why please?
A. Its mass and weight have become equal
B. It has no more potential energy
C. No forces are acting on it any longer
D. The forces acting on it are balanced

Answers

Answer:

A.

Explanation:

If its at a height the Gratitude of it falling down with only Gravity if Any other Forces are acting on it so as Friction But Sideways.

A projectile is projected from the origin with a velocity of 45.0 m/s at an angle of 30.0 degrees above the horizontal. What is the velocity when the projectile hits the ground?

Answers

Answer:

velocity = 44.98 m/s

Explanation:

given data

velocity = 45.0 m/s

angle = 30.0 degrees

solution

first we get here time that is

time = 2u × sin θ ÷ g   .............1

time = 2×45 × sin 30 ÷ 9.8

time = 4.59 sec

and

velocity = [tex]\sqrt{vx^2+vy^2}[/tex]   .....................2

here

vx = 45 cos30 = 38.97 m/s

vy = uy - gt

vy = 45 sin30 - 9.8 ×  4.59  = -22.48 m/s

so velocity will be

velocity = [tex]\sqrt{38.97^2+22.48^2}[/tex]

velocity = 44.98 m/s

What happens to the gravitational potential energy between two particles if the distance between them is halved? (a) It does not change(b) It is multiplied by 2(c) It is multiplied by 4(d) It is multiplied by 8What happens to the gravitational force between two particles if the distance between them is doubled? (a) It does not change(b) It decreases by a factor of 2(c) It decreases by a factor of 4(d) It decreases by a factor of 8

Answers

Answer:

The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).

Explanation:

The gravitational force is the force of mutual attraction that two objects with mass experience.

The Law of Universal Gravitation enunciated by Newton says that every material particle attracts any other material particle with a force directly proportional to the product of their masses and inversely proportional to the square of the distance that separates them. Mathematically this is expressed as:

[tex]F=G*\frac{m1*m2}{r^{2} }[/tex]

where m1 and m2 are the masses of the objects, r the distance between them and G a universal constant that receives  the name of constant of gravitation.

If the distance between two particles is reduced by half, then, where F' is the new value of the gravitational force:

[tex]F'=G*\frac{m1*m2}{(\frac{r}{2} )^{2} }[/tex]

[tex]F'=G*\frac{m1*m2}{\frac{(r )^{2} }{2^{2} } }[/tex]

[tex]F'=G*\frac{m1*m2}{\frac{(r )^{2} }{4} }[/tex]

[tex]F'=4*G*\frac{m1*m2}{r^{2} }[/tex]

F'=4*F

The gravitational potential energy between two particles, if the distance between them is halved, is multiplied by 4 (option c).

A basketball has a coefficient of restitution of 0.821 in collisions with the wood floor of a basketball court. The ball is dropped on such a floor from a height of 2.07 m . How high is its fourth bounce?

Answers

Answer: The height of its fourth bounce = 0.43m

Explanation:

The coefficient of restitution denoted by (e), is the ratio that shows the  final velocity to initial relative velocity between two objects after collision

IT is given by the formula in terms of height as

Coefficient of Restitution, e  = √(2gh))/√(2gH) = √(h/H)

Where

Coefficient of Restitution, e= 0.821

H = 2.07 m

At fourth bounce ,   we have that

Coefficient of Restitution, e⁴  =√(h₄/H)  

Putting the given values and solving , we have,

e⁴  =√(h₄/H)  

= 0.821⁴ = √(h₄/2.07)

 (0.821⁴ )² =h₄/2.07

0.2064 x 2.07 = 0.427 = 0.43

At  fourth bounce,  h₄ height = 0.43m

Telephone signals are often transmitted over long distances by microwaves. What is the frequency of microwave radiation with a wavelength of 3.5 cm?
Express your answer in GHz and using two significant figures.
f = ________GHz
Microwave signals are beamed between two mountaintops 52 km apart. How long does it take a signal to travel from one mountaintop to the other?
Express your answer in ms and using two significant figures.
t = ________ms

Answers

Answer:

1) f= 8.6 GHz

2) t= 0.2 ms

Explanation:

1)

Since microwaves are electromagnetic waves, they move at the same speed as the light in vacuum, i.e. 3*10⁸ m/s.There exists a fixed relationship between the frequency (f) , the wavelength (λ) and the propagation speed in any wave, as follows:

        [tex]v = \lambda * f (1)[/tex]

Replacing by the givens, and solving for f, we get:

       [tex]f =\frac{c}{\lambda} =\frac{3e8m/s}{0.035m} = 8.57e9 Hz (2)[/tex]

⇒     f = 8.6 Ghz (with two significative figures)

2)

Assuming that the microwaves travel at a constant speed in a straight line (behaving like rays) , we can apply the definition of average velocity, as follows:

       [tex]v =\frac{d}{t} (3)[/tex]

       where v= c= speed of light in vacuum = 3*10⁸ m/s

       d= distance between mountaintops = 52 km = 52*10³ m

Solving for t, we get:

       [tex]t = \frac{d}{c} = \frac{52e3m}{3e8m/s} = 17.3e-5 sec = 0.173e-3 sec = 0.173 ms (4)[/tex]

       ⇒  t = 0.2 ms (with two significative figures)

In a binary star system, the average separation between the stars is 5.0 AU, and their orbital period is 5.0 years. What is the sum of their two masses?The average distance of Star A from the center of mass is four times that of Star B. What are their individual masses?

Answers

Answer:

A. 5.03 solar mass.

B. the masses of Star A and B are 1.01 solar mass and 4.02 solar mass respectively.

Explanation:

A. The sum of their two masses can be found using Kepler's third law:

[tex]\frac{P^{2}}{a^{3}} = \frac{4\pi^{2}}{G(m_{A} + m_{B})}[/tex]

Where:

P: is the period = 5 y = 1.58x10⁸ s

a: is the separation between the stars = 5 AU = 7.5x10¹¹ m

G: is the gravitational constant = 6.67x10⁻¹¹ m³kg⁻¹s⁻²

[tex]m_{A}[/tex] and [tex]m_{B}[/tex] are the masses of Star A and Star B respectively.    

[tex]m_{A} + m_{B} = \frac{4\pi^{2}a^{3}}{P^{2}G} = \frac{4\pi^{2}(5 AU*\frac{1.5\cdot 10^{11} m}{1 AU})^{3}}{(1.58 \cdot 10^{8} s)^{2}6.67 \cdot 10^{-11} m^{3}*kg^{-1}*s^{-2}} = 1.00 \cdot 10^{31} kg*\frac{1 M_{\bigodot}}{1.989\cdot 10^{30} kg} = 5.03 M_{\bigodot}[/tex]    

Hence, the sum of their two masses is 5.03 solar mass.  

B. Their individual masses can be found using the center of the mass equation:

[tex] a_{B} = (\frac{m_{A}}{m_{A} + m_{B}})a [/tex]

Where:

[tex]a_{B}[/tex] is the distance of Star B from the center of the mass

Since, [tex]a_{A}[/tex] is four times [tex]a_{B}[/tex] and a = 5 AU we have:

[tex] a_{A} = 4a_{B} [/tex]

[tex] a = a_{A} + a_{B} [/tex]

[tex] a_{B} = a - a_{A} = a - 4a_{B} \rightarrow a_{B} = \frac{a}{5} [/tex]      

Then, their individual masses are:

[tex]\frac{a}{5} = (\frac{m_{A}}{5.03 M_{\bigodot}})a[/tex]  

[tex]m_{A} = \frac{5.03 M_{\bigodot}}{5} = 1.01 M_{\bigodot}[/tex]

Now, the mass of Star B is:

[tex]m_{B} = m_{T} - m_{A} = 5.03 M_{\bigodot} - 1.01 M_{\bigodot} = 4.02 M_{\bigodot}[/tex]

Therefore, the masses of Star A and B are [tex]1.01 M_{\bigodot}[/tex] and [tex]4.02 M_{\bigodot}[/tex] respectively.

I hope it helps you!                              

Which is the MOST accurate description of this type of cell?
O A) It is a eukaryotic cell.
OB) It is a prokaryotic cell.
OC) It does not contain DNA.
OD) It does not contain a membrane-enclosed nucleus.

helpppppppp first person who answers gets a brainly if it’s right

Answers

It would be

O A) It is a eukaryotic cell.

A rotating wheel requires 8.00 s to rotate 27.0 revolutions. Its angular velocity at the end of the 8.00-s interval is 99.0 rad/s. What is the constant angular acceleration (in rad/s) of the wheel?

Answers

Answer:

∝ = 28.92 rad/s²

Explanation:

Applying third equation of motion to the angular motion, we have:

2∝θ = ωf² - ωi²

where,

∝ = angular acceleration = ?

θ = angular displacement = (27 rev)(2π rad/1 rev) = 169.64 rad/s

ωf = final angular velocity = 99 rad/s

ωi = initial angular velocity = 0 rad/s

Therefore,

(2)∝(169.64 rad) = (99 rad/s)² - (0 rad/s²)

∝ = (9801 rad²/s²)/(38.8 rad)

∝ = 28.92 rad/s²

Pete is driving down 7th Street. He drives 300 meters in 18 seconds. Assuming he does not speed up or slow down, what is his speed in meters per second? Round answer to the hundredths place.

Answers

Answer:

16.67m/s

Explanation:

Given parameters:

Distance Pete drove  = 300m

Time taken  = 18s

Unknown:

Speed  = ?

Solution:

Speed is the distance traveled per unit of time.

It is mathematically expressed as;

   Speed  = [tex]\frac{distance}{time}[/tex]

Insert the parameters and solve;

  Speed  = [tex]\frac{300}{18}[/tex]  = 16.67m/s

Object A is 71 degrees and object B is 75 degrees how will thermal energy flow

Answers

Given :

Object A is 71 degrees and object B is 75 degrees .

To Find :

How will thermal energy flow.

Solution :

We know, by law of thermodynamics thermal energy will flow from higher temperature to lower temperature.

So, in the given question energy will flow from object B from object A.

Hence, this is the required solution.

The achilles tendon is subjected to a large tension stress that results in a strain of 6%. if the unloaded tendon is 10 cm long, how much does it elongate as a result of this strain?

The answer is .6cm I need to understand the work to get here.

Answers

Answer: 0.6cm

Explanation:

Strain is defined as  how much an object can be stretched or deformed  when force is applied to it .  it measures the  fractional change of the object’s length when the object faces  tensional stress. It is calculated  by using the formulae

Strain =  ΔL/ L

where strain = 6%

L= Original length

ΔL= change in length

 6% = ΔL/ 10 cm

ΔL= 10cm X 0.06

ΔL=0.6cm

Kathryn decides to take her dog for a walk one day. Her dog tries pulling on her with a force of 15N. Kathryn pulls back with force of 20N. What is the net force?

Answers

Assuming both forces act horizontally, the net force is in Kathryn's direction with a magnitude of 5 N.

If "towards Kathryn" is taken the be the positive direction, then the net force is

F = 20 N - 15 N = 5 N

In a two-slit experiment using coherent light, the distance between the slits and the screen is 1.10 m, and the distance between the slits is 0.0400 mm. If the second order bright fringe is measured to be 4.20 cm from the centerline on the screen, what is the wavelength of light?
A) 620 nm
B) 200 nm
C) 401 nm
D) 763 nm
E) 381 nm

Answers

Answer:

D) 763 nm

Explanation:

Calculation for the wavelength of light

Using this formula

Wavelength of light=Delta Y*Distance / Length

Where,

Delta Y represent the 2nd order bright fringe

Length represent the distance between both the slits and the screen

Distance represent the Distance between the slits

Let note that cm to m = (4.2) x 10^-2 and mm to m= ( 0.0400x 10^-3)

Now Let plug in the formula

Wavelength of light=[(4.2 x 10^-2m)(0.0400 x 10^-3m) / 2(1.1m)]*10^-7 meters

Wavelength of light=[(0.042m) (0.0004m)/2.2m]*10^-7 meters

Wavelength of light =(0.0000168m/2.2m)*10^-7 meters

Wavelength of light =7.63 *10^-7 meters

Wavelength of light =763 nm

Therefore the Wavelength of light will be 763 nm

A ball connected to a 1.1 m string and is swing in circular fashion. It’s tangential velocity is 15 m/s. What is its centripetal acceleration?

Answers

Answer:

ac = 204 [m/s²]

Explanation:

To solve this problem we must use the following equation that relates the tangential velocity to the radius of rotation.

ac = v²/r

where:

v = tangential velocity = 15 [m/s]

r = radius = 1.1 [m]

Now replacing we have:

ac = (15)²/1.1

ac = 204 [m/s²]

If John throws a "ball” from a cliff with a speed of 15 m/s, how far from the bottom of the cliff does it land after 10 seconds?​

Answers

Answer:

wazzam blood

Explanation:

2). If you record a wave going 4m/s and the Period of the wave was
60s, how long was the wave?

Answers

Answer:240 meters

Explanation:60×4

What would happen if there was a sudden increase in the amount of greenhouse gases in Earth’s atmosphere?

Earth would suddenly cool down because more heat would leave the Earth system and go back to space.
Earth would suddenly cool down because solar radiation would not be able to flow through the atmosphere.
Earth would suddenly warm up because more heat from the atmosphere would be radiated toward Earth’s surface.
Earth would suddenly warm up because more heat from the Sun would be allowed to enter the atmosphere.

Answers

Answer:

Earth would suddenly warm up because more heat from the Sun would be allowed to enter the atmosphere.

Explanation:

The greenhouse gasses would make the ozone layer thinner letting in more harmful rays on the sun.

Hope this helps!! :)

Also I need one more brainliest if you dont mind giving it to me :)

Answer:

Earth would cool down because it would reflect more solar radiation.     it would be A.

Explanation:

If the magnetic field of an electromagnetic wave is in the x-direction and the electric field of the wave is in the y-direction, the wave is traveling in the

Answers

Answer:

wave is in the y-direction, the wave is traveling in the

Explanation:

which of the following is an example of projectile motion?
a) a child tumbling down a hillside
b) a bowler rolling her ball down an alley
c) a football in flight during a field goal
d) a surfer riding a wave​

Answers

a football in flight during a field goal
Either b or c. Probably c though

2.
Which statement is true regarding the launch of a rocket?

The downward force of the rocket exhaust is greater than the upward force on the rocket.

The downward force of the rocket exhaust is equal to the upward force on the rocket.

The upward force of the rocket exhaust is equal to the downward force on the rocket.

The downward force of the rocket exhaust is less than the upward force on the rocket.

Answers

Answer:

First one,

Its because

Downward force must greater to uplift its weight.

From 3rd law of motion

Answer:

The downward force of the rocket exhaust is greater than the upward force on the rocket.

Explanation:

Your Welcome (;

A skateboarder is moving at 2.00m/s and increases his velcity at a rate of 1.6m/s/s for 6.0 seconds. What is the displacement of the skateboarder during this game? Must include Given, Find , and Equation. Show all work .

Answers

Answer:

S = 40.8m

Explanation:

Given the following data;

Initial velocity, u = 2m/s

Acceleration, a = 1.6m/s²

Time, t = 6secs

Required to find the displacement

Displacement, S = ?

The displacement of an object is given by the second equation of motion;

[tex] S = ut + \frac {1}{2}at^{2}[/tex]

Where;

S represents the displacement measured in meters. u represents the initial velocity measured in meters per seconds. t represents the time measured in seconds. a represents acceleration measured in meters per seconds square.

Substituting into the equation, we have;

[tex] S = 2*6 + \frac {1}{2}*(1.6)*6^{2}[/tex]

[tex] S = 12 + 0.8*36[/tex]

[tex] S = 12 + 28.8 [/tex]

S = 40.8m

Therefore, the displacement of the skateboarder during this game is 40.8 meters.

Does the weight of the projectile affect the horizontal range?

Answers

Answer:

no

Explanation:

This downward force and acceleration results in a downward displacement from the position that the object would be if there were no gravity. The force of gravity does not affect the horizontal component of motion; a projectile maintains a constant horizontal velocity since there are no horizontal forces acting upon it.

A horizontal force of 100 N is required to push a 50 kg crate across a factory floor at a constant speed. What is the acceleration on the cart?​

Answers

Answer:

a = 2m/s^2

Explanation:

Force (F) = 100 N

Mass (m) = 50 kg

Here,

F = m×a

100 = 50 × a

a = 100÷50

a = 2m/s^2

Thus, the acceleration on the cart is a = 2m/s^2

-TheUnknownScientist

An object at rest will stay at rest, and an object in motion will stay in
motion, unless acted upon by an unbalanced force is known as which Law
of Motion?

Answers

Answer:

It is Newton's first law of motion also referred  to as the law of inertia.

Explanation:

The transfer of thermal energy between objects of different
temperatures is called...

A.) Heat
B.) Temperature
C.) Specific Heat
D.) Internal Energy

Answers

Answer:

A

Explanation:

heat transfer occurs between two objects that are not in thermal equilibrium (do not have the same temperature)(heat flows from hot to cold objects)

temp= measure of how hot/cold something is

internal E= total E of a closed system

The transfer of thermal energy between objects of different temperatures is called Heat.

What is heat?

Heat is the energy transferred from one object to another as a result of a temperature differential. When two bodies of different temperatures come into contact, energy is transferred—that is, heat flows— towards the colder body from the hotter.

As we know that when two bodies are not in thermal equillibrium then the heat starts to flow, from the higher temperature body towards the lower temperature body. Thus, The transfer of thermal energy between objects of different temperatures is called Heat.

Learn more about Heat:

https://brainly.com/question/1429452

What is the key variable for calculating potential energy?

Answers

The formula for potential energy depends on the force acting on the two objects. For the gravitational force the formula is P.E. = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s2 at the surface of the earth) and h is the height in meters.

where is information first stored in a human brain​

Answers

Answer:

when u learn something new it goes to ur short term memory

My solar system has two types of planets: terrestrials and jovians. The solar nebula hypothesis offers what explanation for the different compositions of these two types of planets? A. The large gravitational forces of Jupiter tended to prevent planet formation in the inner solar system and eventually attracted most of the material into the region of the Jovian planets. B. During condensation, the heavier elements tended to sink nearer the Sun and, being rare, only provided enough material to build the relatively small terrestrial planets. C. The terrestrial planets were formed near the Sun where, because of the high temperatures, only heavier elements were able to condense. D. During the collapse of the gaseous nebula, most of the material tended to collect far from the Sun because of the large centrifugal forces, which provided the necessary material to build the large Jovian planets.

Answers

Answer:

B. During condensation, the heavier elements tended to sink nearer the Sun and, being rare, only provided enough material to build the relatively small terrestrial planets.

D. During the collapse of the gaseous nebula, most of the material tended to collect far from the Sun because of the large centrifugal forces, which provided the necessary material to build the large Jovian planets.

Explanation:

The solar nebular hypothesis is the theory of how the earth came to be as proposed and believed by most scientists. It states that the solar system was formed from a nebular which is a large collection of dust. As the condensation of the nebular progressed, the heavier materials which could withstand higher temperatures formed closer to the sun. Because these materials were not so much the planets formed by them were not large in size.

However, the Jovian planets formed beyond the frost line which could sustain icy compounds. The ices that formed these planets were much thus accounting for their larger sizes. Solar winds blew off the lighter hydrogen and helium elements leading to their accumulation far away from the sun.

The half-life of a substance is 10 years. What percent of the substance remains after 2 half-lives.

need answer asap. i think its 2.5 but not sure

Answers

Answer:

i think its 2.5 as well

Explanation:

Which of the following is not one of the four muscle shapes?
A. Triangular
B. Flat
C. Spindle
D. Cylindrical

Answers

Answer:

When elements bond together or when bonds of compounds are broken and form a new substance

Explanation:

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