Answer:
1) combustion can be used as a source of energy.
Combustion is used to power rockets
ii) Decomposition of sugar is a chemical change and new substances are formed.
2)corrosion of pipes
Corrosion of bridges
Corrosion of knives and blades at home
I) iron rusts due to the action of air and moisture bon the metal setting up an electrochemical process in which the iron is the anode. This leads to the corrosion of the iron metal.
ii) Rusting is a problem because it reduces the economic value of iron. Rust weakens iron and threatens the integrity of materials made from iron.
Iron rusting may lead to the collapse of a bridge
Iron rusting makes a blade blunt
Iron rusting weakens pipes made of iron
iii) Rusting of iron can be prevented by galvanizing the iron or by painting the iron.
3) chemical change leads to the formation of a new substance while physical change does not lead to the formation of a new substance.
Chemical changes are not easily reversible while physical changes are easily reversible.
ii)condensation of water vapour is a physical change
iii)
Electrolysis of water;
Two moles of water---> two moles of hydrogen gas + one mole of oxygen gas
Synthesis of water;
two moles of hydrogen gas + one mole of oxygen gas---->Two moles of water
Decomposition of sugar;
One mole of Sucrose---> twelve moles of carbon + eleven moles of water + heat
Six moles of carbon dioxide + six moles of water +energy------> one mole of sugar + six moles of oxygen
Explanation:
Combustion is useful as a source of energy because it is used in power generation. Currently, combustion is being used to power rockets. It is also used as a way of providing heat at home.
One of the characteristics of a chemical change is that it leads to the formation of new substances. Since the decomposition of sugar leads to the formation of carbon and water, it is an irreversible chemical change.
When water is heated, it is converted into vapour which can settle on a surface and convert back to liquid water. This is a physical change.
The amplitude of a particle executing simple harmonic motion is 5cm, while its angular velocity is 10 rads -1 . Calculate the magnitude of the maximum acceleration of the particle.
Answer:
a_max = 50 cm/s^2
Explanation:
To find the magnitude of the maximum acceleration of the particle, you take into account the equation of motion in a simple harmonic motion:
[tex]x=Acos(\omega t)[/tex]
ω: angular velocity = 10 rad/s
A: amplitude = 5 cm
The acceleration is given by:
[tex]a=\omega^2 x[/tex]
and the maximum acceleration is obtained when the cosine function is maximum, that is, when cos(wt) = 1. Then, you have:
[tex]a_{max}=\omega^2 x_{max}=\omega^2A[/tex]
Then, you replace the values of w and A in order to calculate a_max:
[tex]a_{max}=(10rad/s)^2(5cm)=50\frac{cm}{s^2}[/tex]
hence, the maximum acceleration is 50 cm/s^2
conditions for equilibriam
A closed-pipe resonator has a length of 1.73 m. The frequency of its second harmonic if the speed of sound is 343 m/s is: a)49,5 Hz b)99.13 Hz c)20.6 Hz d)72 Hz
Answer:
There is no answer, since a closed-pipe resonator can NOT have a second harmonic. However, if you were to plug the pipe length and the speed of sound into the closed-pipe equation anyway you would get 49.56 as your fundamental frequency, which means that 99.13 would be your "plug and play" 2nd harmonic.
Explanation:
why does a balloon filled with hydrogen rises up only to a certain height
Answer: they will rise up because hydrogen is lighter in density and it's weight is lower when it's in the air
Explanation:
Answer:
hydrogen is less dense and its weight is also less than the air.
Explanation:
Explain how series circuits use current and voltage and Explain how parallel circuits use current and voltage
'''In a series circuit, the sum of the voltages consumed by each individual resistance is equal to the source voltage. Components connected in parallel are connected along multiple paths so that the current can split up; the same voltage is applied to each component.''
i reallllly need someone to answer this quick. it's fine if you can't though
Answer:
The correct order of answers goes:
[tex]\left[\begin{array}{ccc}Ionic\\Electronegativity\\Metallic\\Cation\end{array}\right][/tex]
Explanation:
Ionic - Ionic bonds are formed between a metal and a nonmetal (typically). Nonmetals are typically more electronegative elements because they are seeking to gain electrons to achieve atomic stability while metals want to give up electrons to those elements to become atomically stable. Therefore, the nonmetals are much more electronegative in comparison to the metals.
Electronegativity - Electronegativity is used mathematically to predict the type of bond that will occur between elements. The larger electronegativity has the smaller electronegativity subtracted from it to give us a number that we then apply to ranges within a table and try to decipher what kind of bond will be formed.
Metallic - This plays into both explanations already given. Metallic bonds will form between metals, meaning their electronegativities will be much lower. Higher differences between electronegativities (anything above 1.7) is considered ionic, while anything from 0.1 to 1.69 is considered covalent (these split to make polar and nonpolar covalence).
Cation - Cation is the term for a positively charged ion. It comes from cathode (a scientist completed an experiment with the cathode ray tube where they accelerated positively charged particles throughout it).
Just need the answer to D please
The boat has to pull with MORE force. Don't forget about the force of friction with the water, pulling the skier in the backwards direction. The force that accelerates him is the NET force ... boat force minus water resistance. So the boat force has to be greater than the net accelerating force.
A lonely child is swinging on a rusty old swing set, as seen in the image provided. If friction does 145 J of work slowing the swing, what is the maximum speed she can reach?
Answer:
2.331
Explanation:
It just the change of Energy from potential (PE) to kinetic (KE)
PE on A = PE on B + KE on B + friction works (Wf)
mg(ha) = mg(hb) + ½mv² + Wf
35 * 9.8 * 1.5 = 35 * 9.8 * 0.8 + ½ * 35 * v² + 145
514.5 = 274.4 + 17.5v² + 145
514.5 - 274.4 - 145 = 17.5v²
17v² = 95.1
v² = 5.434
v =√5.434 = 2.331 m/s
An injured monkey sits perched on a tree branch 9 m above the ground, while a wildlife veterinarian is kneeling down in the bushes 90.0 m away attempting to subdue the monkey with a tranquilizer gun. The vet knows that the moment the gun fires, the monkey will be frightened and fall down from the branch. At what angle up from the ground must the veterinarian aim the gun so that the tranquilizer dart will hit the falling monkey? Given the angle, what is minimum speed at which the tranquilizer dart must leave the gun to still hit the monkey?
Answer:
The hunter should aim directly at the perched monkey because the tranquilizer dart will fall away from the line sight at the same rate that the monkey falls from its perch.
Tan theta = 9 / 90 = .1 so theta = 5.71 deg
The time for the monkey to reach the ground is
t = (2 h / g)^1/2 = (18 / 9.8)^1/2 = 1.36 sec
So the horizontal speed of the dart must be at least
Vx = 90 m / 1.36 sec = 66.4 m/s
Vx = V cos theta
V = 66.4 m/s / cos 5.71 = 66.7 m/s
The angle of projection of the tranquilizer dart is 5.7⁰
The horizontal speed of the tranquilizer dart is 66.5 m/s
The given parameters;
vertical position of the monkey, y = 9 mhorizontal position of the veterinarian, x = 90The angle of projection of the tranquilizer dart is calculated as;
[tex]tan(\theta) = \frac{y}{x} \\\\tan(\theta) = \frac{9}{90} \\\\tan(\theta) = 0.1\\\\\theta = tan^{-1}(0.1)\\\\\theta = 5.71 ^0[/tex]
The speed of the tranquilizer dart is calculated as;
X = v₀ₓt
where;
t is the time to reach maximum height
X is the horizontal displacement = 90 m
The time to reach maximum height is calculated as;
[tex]h = v_0_yt + \frac{1}{2} gt^2\\\\h = 0 + \frac{1}{2} gt^2\\\\h = \frac{1}{2} gt^2\\\\t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2\times 9}{9.8} } \\\\t = 1.36 \ s[/tex]
The horizontal speed of the tranquilizer dart is calculated as;
[tex]X = v_0cos(\theta) \times t\\\\90 = v_0\times cos(5.71) \times 1.36\\\\90 = 1.353 v_0\\\\v_0= \frac{90}{1.353} \\\\v_0 = 66.5 \ m/s[/tex]
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What happens when a sound wave passes from water into air
Answer:
Explanation:
Sounds travel faster in object having high density proportion or matter. This is because particles vibrates and causing the other particle near to as well vibrate. Hence, when sound is moving from a higher dense medium like Water, the rate of traveling is high compare to it moving in air with less dense.
A cork weigh 2.5 gf in air. When tied to a sinker , the total weight is 20 gf in water. If the sinker alone weighs 25gf in water, find the density of the cork
Answer:
0.333
Explanation:
Weight of the sinker in water = 25gf
Weight of cork in air and sinker in water = 25gf + 2.5gf
= 27.5gf
Weight of the cork and sinker in water = 20gf
Loss of weight of cork in water = 27.5- 20 = 7.5gf
Rd of cork = weight of cork in air/ loss of weight of cork in water
= 2.5/7.5
= 1/3
= 0.333
Hence the Relative density of the cork is 0.333
Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (b) a bicycle and a train? (c) a five-rupees coin and a one-rupee coin?
Inertia is the same thing as mass, more or less. Inertia is the tendency of the object to want to stay in place if at rest, or the object's tendency to stay in motion if a force is applied to it. A train's inertia is massive because it takes a lot of force to move such a large mass, or to slow it down. This is in comparison to the other objects (rubber ball, stone, bike, and the coins).
Answer:
Inertia is the measure of the mass of the body. The greater is the mass of the body; the
greater is its inertia and vice-versa.
(a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of
the stone is greater than that of a rubber ball.
(b) Mass of a train is more than the mass of a bicycle. Hence, inertia of the train is greater
than that of the bicycle.
(c) Mass of a five rupee coin is more than that of a one-rupee coin. Hence, inertia of the five
rupee coin is greater than that of the one-rupee coin.
Which of the following characterizes the particles in this diagram?
A. Two positive charges
B. One positive charge and one negative charge
C. Two negative charges
D. Two neutral charges
Answer:
B
Explanation:
One positive charger and one negative charger
A force acting on a body of mass 200g displace it through 200cm in 5s. Find the magnitude of the force if the initial velocity of is Zero
Answer:
F = 0.32 N
Explanation:
GIVEN:
Mass = m = 200 g = 0.2 kg
Distance = S = 200 cm = 2 m
Time = t = 5 s
Initial velocity = U = 0 m/s
REQUIRED
Force = F = ?
SOLUTION
Using Second Equation of Motion,
S = Ut + 1/2 at²
2 = (0)(5) + 1/2 a(5)²
2 = 25/2 a
a = 4/25
a = 0.16 m/s²
So,
Acceleration = a = 0.16 m/s²
Now Using Equation from Newtons Second Law of Motion
F = ma
F = (2)(0.16)
F = 0.32 N
A cord is wrapped around the outer surface of the 8-kg disk. If a force of F = (1⁄4u2) N, where u is in radians, is applied to the cord, determine the disk’s angular acceleration when it has turned 5 revol
A cord is wrapped around the outer surface of the 8-kg disk. If a force of F = (1⁄4θ²) N, where θ is in radians, is applied to the cord, determine the disk’s angular acceleration when it has turned 5 revolutions. The disc has an initial angular velocity [tex]\omega _o = 1 \ rad/s[/tex] and radius from the center of the disc = 300 mm
Answer:
the angular acceleration = 205.706 rad/sec²
Explanation:
GIVEN THAT:
The disc mass = 8 kg
Force = [tex]\dfrac{1}{4} \ \ \theta ^2* N[/tex]
We are told that the given θ is in radians; Therefore; the when it has turned 5 revolutions; we have the θ to be:
[tex]\theta = 5 rev * (\dfrac{2 \ \pi * rad}{1 rev}) \\ \\ \theta = 10 \ \pi \ rad[/tex]
Also;
the initial angular velocity [tex]\omega _o = 1 \ rad/s[/tex]
radius from the center of the disc = 300 mm = 0.3 m
Thus; the mass moment about the Inertia can be determined via the following expression;
[tex]I_o = \dfrac{1}{2}*m*r^2[/tex]
[tex]I_o = \dfrac{1}{2}*8*0.3^2[/tex]
[tex]I_o = 0.36 \ kg/m^3[/tex]
Now to calculate the angular acceleration; we equate the sum of the moments acting on the Inertia;
SO:
[tex]\sum M_o = I_o \alpha[/tex]
[tex]F*0.3 = 0.36* \alpha[/tex]
[tex]\dfrac{1}{2}* \theta^2 *0.3 = 0.36* \alpha[/tex]
[tex]\alpha = 0.20836 \ \theta^2 \ rad/sec^2[/tex]
[tex]\alpha = 0.20836 \ (10 \ \pi )^2 \ rad/sec^2[/tex]
[tex]\alpha = 205.706 \ rad/sec^2[/tex]
Hence; the angular acceleration = 205.706 rad/sec²
Suppose that you walk 15 meters at 30 degrees as measured from the East. Then you walk another 25 meters at 60 degrees from the East what is your net displacement
Answer:
The net displacement is
[tex]R= \sqrt{A^2+B^2+2AB \cos \theta}[/tex]
[tex]=\sqrt{15^2+25^2+2AB \cos 30^\circ} \\\\=\sqrt{225+625+ \cos30^0} \\\\=38.7m[/tex]
Explanation:
Suppose that you walk 15 meters at 30 degrees as measured from the East. Then you walk another 25 meters at 60 degrees from the East what is your net displacement
Given data
A = 15 m
B = 25 m
Angle between the vectors A and B is θ = 30°
The net displacement is
[tex]R= \sqrt{A^2+B^2+2AB \cos \theta}[/tex]
[tex]=\sqrt{15^2+25^2+2AB \cos 30^\circ} \\\\=\sqrt{225+625+ \cos30^0} \\\\=38.7m[/tex]
4. ____________ occurs when one object slides over another.
a. Sliding friction
b. Static friction
c. Rolling friction
d. Net force
Answer:
A. Sliding friction
Explanation:
Sliding friction is weaker than static friction
Answer:
Rolling Friction
Explanation:
I know this because the definition of rolling friction is : type of friction that happens when one body rolls over another
potential energy is frequintly converted into kenetic energey. kenetic energey
Answer:
When an object falls, its gravitational potential energy is changed to kinetic energy. ... Gravitational potential energy for a mass m at height h near the surface of the Earth is mgh more than the potential energy would be at height 0. (It's up to you where you choose height 0.)
Explanation:
Answer:
Qwertyujiknb vcdxrftyhbvcdxrft6y7uij
Explanation:
Assume that a machine puts out 8000 joules of work when the user puts in 10,000 joules of work. What is the efficiency of the machine?
Answer:
80 Percent
Explanation:
E=energy output/energy input×100
E=8000/10000×100
E=0.8×100
E=80 percent.
Mark brianliest if my answer suit your question
If the machine put, in 8000 J, and the user puts 10,000 J of work then the efficiency of the machine will be equal to 80%.
What is Work?Work is a physics term used to describe the transfer of energy that takes place when an object changes above a distance because of an external force, at least some of which is given in the vector of the dislocation. The element of the force acting all along the path multiplied by the length of the path can be used to calculate work if the force is constant.
Mathematically, this idea is expressed as W = fd, where W is the effort and f is the force multiplied by d, the distance. Work is completed whenever the force is applied at an angle with about the displacement.
As per the data provided in the question,
Total input energy = 10,000 J
Total output energy = 8,000 J
Then, the efficiency (η) of the machine will be,
η = (output energy/input energy) × 100
η = 8000/10000 × 100
η = 80%.
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Question 1 of 25
2 Points
What is the kinetic energy of a 5-kg cat chasing a mouse across the yard at 2
m/s?
A. 98 J
B. 10 J
C. 2J
D. 20 J
SUBMIT
Explanation:
K = 5kg[tex](2 m/s)^{2}[/tex]/2 = 10 J
Jess wants to make her house more energy efficient. She has two options, A or B. Option A is double-glazing her patio doors, which will cost £350 and save £15 per year. Option B is insulating her loft, which will cost £460 and save £25 per year. Is option A or option B the better long-term option?
Jess wants to make her house more energy efficient. Insulating her loft, which will cost £460 and save £25 per year, is better long-term option. Therefore, option B is correct.
What is energy ?In order to accomplish work and to produce heat and light, energy must be transferred to a body or to a physical system. Energy is the quantitative attribute that does this. Energy is a preserved resource; according to the rule of conservation of energy, energy can only be transformed from one form to another and cannot be created or destroyed.
Computers, vehicles, communications, state-of-the-art medical technology, and many other things are all powered by energy. The demand for dependable and economical energy is especially pressing for emerging countries. It may enhance things or perhaps save lives.
A turbine generator set transforms mechanical energy into electrical energy to produce electricity. Natural gas, coal, nuclear fission, biomass, petroleum, geothermal, and solar thermal are examples of energy sources where the heat generated is used to produce steam.
Thus, option B is correct.
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what is light rays ?
Answer:
A light ray is a line (straight or curved) that is perpendicular to the light's wavefronts
Explanation:
Have a great day.
A water distiller which is used to purify water. The distiller boils water and then condenses most of the water vapour back to water. (a) The water distiller is filled with 5.0 kg of water at 20 °C The specific heat capacity of water = 4 200 J/Kg °C Calculate the energy needed to raise the temperature of the water to 100 °C ___________________________________________________________________
Answer:
Energy needed 1680kJExplanation:
The quantity of heat required to raise the temperature of water to 100 degrees is expressed as
[tex]Q= mc(T2-T1)[/tex]
Given data
mass of water = 5kg
initial temperature T1= 20 °C
final temperature T2= 100 °C
Specific heat capacity of water= 4 200 J/Kg °C
[tex]Q= 5* 4 200(100-20)\\Q= 21000(80)\\Q= 1680000\\Q= 1680kJ[/tex]
In a 30cm by 25cm rectangle, a quadrant of a circle of radius 7cm has been cut away from each corner. What is the perimeter of the part left?
Answer: 98cm
Explanation:
Dimension of rectangle = 30cm by 25cm
Length(l) = 30cm
Width(w) = 25cm
Perimeter of a rectangle = 2(l + w)
Quadrant of circle cut away of each side of the rectangle :
Radius = 7 cm =
That is, the dimension of the triangle reduces by 2 * 7 = 14cm
New length = 30 - 14 = 16cm
New width = 25 - 14 = 11cm
The four corners =( 4 × 2πr ) / 4
2πr = 2 × 22/7 × 7 = 44cm
Perimeter = 2(16cm + 11cm)
= 2(27cm)
Perimeter = 54cm + 44 = 98cm
In the equation for elastic potential energy below, what is represented by the symbol k? Ee = ½ × k × e²
Answer:
K is the spring/elastic constant measured in Newton per metre square (N/m²)
Explanation:
E = ½Ke²
In the equation above,
E is the energy in Joules (J)
K is the elastic/spring constant in Newton per metre square (N/m²)
e is the extension in metre (m)
Answer:
In the equation Ee = ½ × k × e², "k" = spring constant
Explanation:
A) Is it possible for an object that, object with zero acceleration have velocity? If yes give an example if not give its proof.
Answer:
Yes, in case of uniform velocity
Explanation:
This is the case of uniform velocity. If a body covers equal displacement in equal intervals of time, then the velocity of a body is said to be ‘Uniform Velocity’. It meas that the velocity of a body remains constant during the motion and it does not change.
Since, acceleration is defined as the rate of change of velocity.
Therefore, if there is no change in velocity or in other words the change in velocity is zero, then the acceleration is also zero.
a = ΔV/t = 0/t
a = 0 m/s²
So, the acceleration of the body is 0 m/s², but it has a uniform velocity
Hence, it is possible for an object that, object with zero acceleration have velocity, which is the case case of uniform velocity.
what is a depletion layer
a vector points 12.0 units along the x-axis and 9.00 units along the y-axis. find the magnitude of the vector
Explanation:
R = [tex]\sqrt{(12.0)^{2} + (9.00)^{2}}[/tex] = 15 UNIDADES
please answer this question first one to answer the right answer will be marked brainiest
Answer: Force per unit area. Explanation: P = 25/20. P = 5/4 Pascal or 1.25 Pascal
Explanation: is this what you were looking for
would iron and carbon form metallic bonds
Answer:
NO.
Explanation:
METALLIC BOND IS ONLY IN METALS.
Since iron is a metal and carbon a non- metal, they cannot form a metallic bond.