Why is the contribution of the wavelets lying on the back of secondary wave front zero?
Answer:
The contribution of the wavelets lying on the back of the wave front is zero because of something known as the Obliquity Factor. It is assumed that the amplitude of the secondary wavelets is not independent of the direction of propagation, Sources: byju's.com
According to the Voigt and Kirchhoff's law for wavelets, the contribution of a wavelet in any direction making an angle x with the normal to the wavelet is proportional to {1+cos(x)/2)}
For wavelet lying on the back of secondary wavefront,
x = 180°→ So, the proportional factor:
→ {1+cos(180°)/2}
→ (1-1/2)
→ (0/2)
→ 0
That's why the contribution of the wavelets lying on the back of secondary wave front is zero
Study the image.
Which of the following choices best explains how the lever made the task easier?
The final force on the rock was the same as the original force from the person and the distance the rock traveled was smaller than the original distance the lever moved, so the total work decreased.
The final force on the rock was greater than the original force from the person and the distance the rock traveled was smaller than the original distance the lever moved, but the total work remained the same.
The final force on the rock was smaller than the original force from the person and the distance the rock traveled was greater than the original distance the lever moved, so the total work stayed the same.
The final force on the rock was greater than the original force from the person and the distance the rock traveled was the same as the original distance the lever moved, so the total work increased.
The final force on the rock was smaller than the original force from the person and the distance the rock traveled was greater than the original distance the lever moved, so the total work stayed the same.
What is the law of conservation of energy?The law of conservation of energy states that energy can neither be created nor destroyed but can be transformed from one form to another.
The total work done on the process will be conserved.
The lever is a simple machine which makes work easier by reducing the force applied to the load and increasing the distance traveled by the load.
Thus, the final force on the rock was smaller than the original force from the person and the distance the rock traveled was greater than the original distance the lever moved, so the total work stayed the same.
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Describe the mechanisms by which out-of-plane deformation in the laser forming
process can occur. As part of your answer, identify the mechanism of laser forming
which is active for the experimental results provided.
The mechanisms by which out-of-plane deformation in the laser forming process can occur include:
Temperature gradient mechanismBuckling mechanismUpsetting mechanism.What is Temperature gradient mechanism?This is the mechanism which involves bending the sheet to a laser light source.
The experiment shown in this scenario depicts it as one plane of the sheet can be seen raised.
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how much force is required to accelerate an 8.6kg wagon by 15 m/s ?
The amount of force required to accelerate the given mass of the wagon is 129 Newtons.
What is force?A force is simply referred to as either a push or pull of an object resulting from the object's interaction with another object.
From Newton's Second Law, force is expressed as;
F = m × a
Where is mass of object and a is the acceleration.
Given the data in the question;
Mass of the rock m = 8.6kgAcceleration a = 15m/s²Force F = ?F = 8.6kg × 15m/s²
F = 129kgm/s²
F = 129N
Therefore the amount of force required to accelerate the given mass of the wagon is 129 Newtons.
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A car travels a distance of 200 miles in 3.5 hours in a given trip. What is the average speed of the car in that
trip? Write the data given, equation, substitution and the answer with correct units for full credit.
Taking into account the definition of speed, the average speed of the car in the trip is 57.14 [tex]\frac{miles}{hour}[/tex].
Definition of speedSpeed is a physical magnitude that relates the displacement of an object and the time it takes to make this change in position.
So, the speed can be defined as the amount of space traveled per unit of time with which a body moves and can be calculated using the expression:
[tex]speed=\frac{displacement}{time}[/tex]
Speed has units of [tex]\frac{distance}{time}[/tex], such as [tex]\frac{meters}{second}[/tex] or [tex]\frac{miles}{hour}[/tex].
Average speed of the carIn this case, you know that:
displacement= 200 milestime= 3.5 hoursReplacing in the definition of speed:
[tex]speed=\frac{200 miles}{3.5 hours}[/tex]
speed= 57.14 [tex]\frac{miles}{hour}[/tex]
Finally, the average speed of the car in the trip is 57.14 [tex]\frac{miles}{hour}[/tex].
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Three sticks are arranged to form a right triangle. If the lengths of the three sticks are 0.47 m, 0.62 m and 0.78 m, what are the three angles of the triangle?
The angles in the triangle are 91 degrees, 53 degrees and 36 degrees respectively.
What is the cosine rule?From the cosine rule we know that;
c^2 = a^2 + b^2 - 2abcosC
Since;
a = 0.47 m
b = 0.62 m
c = 0.78 m
Then;
(0.78)^2 = (0.47)^2 + (0.62)^2 - 2(0.47 * 0.62)cosC
0.61 = 0.22 + 0.38 - 0.58 cosC
0.61 - ( 0.22 + 0.38) = - 0.58 cosC
0.01 = - 0.58 cosC
C = cos-1(0.01/-0.58)
C = 91 degrees
Using the sine rule;
b/Sin B = c/Sin C
0.62/sinB = 0.78/sin 91
0.62/Sin B = 0.78
B = sin-1 (0.62//0.78)
B = 53 degrees
Angle A is obtained from the sum of angles in a triangle;
180 - (91 + 53)
A = 36 degrees
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As elements gain more electrons in their outer shells, their electrical
conductivity generally decreases. Which of the following explains this
phenomenon?
Electrical conductivity often decreases, when elements receive additional electrons in their outer shells. As a result of the valence shell being filled, the number of movable electrons decreases.
What is a mobile electron?Electrons are mobile charges in the conduction band while holes are mobile charges in the valence band.
Current flow in a semiconductor is caused by charge carrier migration in both the conduction and valence bands.
Which creates a net motion of positively charged carriers in the same direction as the field and negatively charged carriers in the opposite direction as a result of the force.
The outermost electrons in metals are not bonded to each atom which is shared by many atoms. This decentralization is what allows metals to conduct electric currents.
Hence, the elements gain more electrons in their outer shells, and their electrical conductivity generally decreases.
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A sewing machine uses 1.6kWh of electricity in one day. If electricity costs 9p per unit, what is the total cost in pence of using the sewing machine that day? Give your answer to 3 significant figures.
Answer:
[tex]\huge\boxed{\sf 1.6\ units = 14.4p}[/tex]
Explanation:
Since,
1 kWh = 1 unitSo,
1.6 kWh = 1.6 units
If,
1 unit = 9p1.6 units = 9p × 1.6
1.6 units = 14.4p
[tex]\rule[225]{225}{2}[/tex]
How much weight can be placed on the spring so that the end of the spring is 2m above the ground?
The weight must be 288N placed on the end of the spring when it is 2m from the ground.
What is gravitational potential energy?If an object is lifted, work is done against gravitational force. The object gains energy.
Given is a spring has a spring constant of 48 N/m. The end of the spring hangs 8 m above the ground. The final height of weight above the ground, h =2m
Using Hooke's law, expressed as
Force, F = k (x₂-x₁).
Put the values, we get
F = 48 (8-2)
F = 288 N
This force applied on the spring is equal to the weight placed on the spring.
Weight W= 288N.
Thus, the weight must be 288N.
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What kind of weather ,begin emphasis,most,end emphasis, likely happens in the town when the air masses meet?
Storm weather likely happens in the town when the air masses meet because of difference of temperature and humidity of both air masses.
What weather happens when air masses meet?
When air masses move by wind, they carry different weather conditions from the weather conditions of other region. This difference in weather conditions can create a severe storm.
So we can conclude that Storm weather likely happens in the town when the air masses meet because of difference of temperature and humidity of both air masses.
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A duck has a mass of 2.70 kg. As the duck paddles, a force of 0.110 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.220 N in a direction of 47.0° south of east. When these forces begin to act, the velocity of the duck is 0.120 m/s in a direction due east. Find (a) the magnitude and (b) the direction (relative to due east) of the displacement that the duck undergoes in 2.70 s while the forces are acting. (Note that the angle will be negative in the south of east direction.)
a) The magnitude will be 0.838m
b) The displacement will be -17.35°
What is displacement?The path covered by an object from its initial point to final point.
Forces acting on the duck
x-axis: 0.13 + 0.16*cos(-56°) = 2.7 * ax
ax = 0.0813 m/s^2
y-axis: 0.13*sin(-56°) = 2.7 * ay
ay = -0.0491 m/s^2
The displacement on the x-axis
X = Vox * t + ax/2 * t²
X = 0.12* 3.2 + 0.0813/2*3.2²
X = 0.8
The displacement on the y-axis:
Y = Voy * t + ay/2 * t²
X = 0 - 0.0491/2*3.2²
Y=-0.25m
So, the magnitude and angle of this displacement [0.8,-0.25] is:
0.838m at an angle of -17.35°
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sketch an electric field pattern around two identical negative point charges shown below in the figure of class 11 model question physics.
Answer:
fv nfv f n f vjrkfv frnv thrfn htrfn vt
Explanation:
v ntv tfrv tn vtv jr4v t5o vtv tv tv
Uranium-235 Fission
Given: energy released = about 200 MeV per individual reaction (mass = 235 amu)
Part A
Find the balanced nuclear reaction.
In the balanced nuclear reaction of uranium 235, we have thorium 231, helium atom and energy released at the right of the equation
Balanced nuclear reaction of UraniumThe balanced nuclear reaction of uranium is determined as follows;
[tex]^{235}_{92}U\ --- > \ ^4_2He\ + \ ^{231}_{90}Th\ + \ energy[/tex]
Thus, in the balanced nuclear reaction of uranium 235, we have thorium 231, helium atom and energy released at the right of the equation while uranium 235 is on the left hand side of the nuclear reaction equation.
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What is ima of the
doorknob
Answer:
ima of the doornob is a show. they have a movie secires too
Explanation:
Assume that the thickness of the tissue between the interior and the exterior of the body is =3 cm and that the average area through which conduction can occur is =1.5 m2 . Find heat transferred by conduction per hour if temperature difference between the inner body and the skin is ∆ = 2 0C. Coefficient of thermal for tissue without blood is = 18 × 10−2 Cal /m-hr- 0C.
The heat transferred by conduction per hour if temperature difference between the inner body and the skin is ∆ = 2°C is 18 Joule/ hr.
What is heat conduction?Heat conduction is the method of transfer of heat by the direct contact of the two or more solid bodies.
Given is the thickness of tissue x = 3cm =-0.03m, Area of conduction A = 1.5 m², Change in temperature of skin ΔT =2°C, and coefficient of thermal for tissue without blood is k = 18 × 10⁻² Cal /m-hr- °C
The conduction heat rate in hr is
Q =kAΔT /x
Q =18 × 10⁻² x 1.5 x 2 /0.03
Q =18 Joule / hr
Thus, the heat transferred by conduction per hour, if temperature difference between the inner body and the skin is ∆ = 2°C is 18 Joule/ hr.
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A person is hauling their taco stand and it takes 3,500 Joules of work to stop the taco stand. What force was exerted on the taco stand if it took 1.5 meters to stop the motion?
Given the work done, the force exerted on the taco stand through the given distance is 2.3 × 10³ Newtons.
What is Work done?Work done is simply defined as the energy transfer that takes place when an object is either pushed or pulled over a certain distance by an external force. It is expressed as;
W = f × d
Where f is force applied and d is distance travelled.
Given that;
Work done W = 3500J = 3500kgm²/s²Distance covered d = 1.5mForce applied F = ?W = f × d
3500kgm²/s² = f × 1.5m
f = 3500kgm²/s² ÷ 1.5m
f = 2.3 × 10³ kgm/s²
f = 2.3 × 10³ N
Given the work done, the force exerted on the taco stand through the given distance is 2.3 × 10³ Newtons.
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The rubber band contains .......potential energy as it is stretched.
less
more
same
Answer:
elastic potential energy
You input potential (stored) energy into the rubber band system when you stretched the rubber band back. Because it is an elastic system, this kind of potential energy is specifically called elastic potential energy.
Explanation:
Why is the human population unique in its ability to affect the environment?
Our population is very large.
We use a lot of resources.
Our population is growing quickly.
All of the above.
Subect: science (not sure if this means pyhsics or chemistry)
Answer:
All of the above
Explanation:
hope it helps you
I need help with this question (open-ended question) 50 points (NO BOTS!!!)
Choose TWO locations below (A, B, C) and provide a two-sentence weather forecast for that location. Your forecast must include Wind direction, general wind speed (high, moderate, low) general temperatures (cold, cool, mild, warm, hot), and sky conditions(precipitation/stormy, sunny cloudy).
The weather forecast for the locations includes:
London - 21°C°, Precipitation: 60%, Humidity: 79%, Wind: 11 km/h.
New York - 26°C°, Precipitation: 50%, Humidity: 76%, Wind: 19 km/h.
What is weather?It should be noted that weather is the state of the atmosphere with respect to heat or cold, calm or storm, clearness or cloudiness.
Weather forecast is an analysis of the state of the weather in an area with an assessment of the likely developments.
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Is the following chemical reaction balanced?
2H₂O2H₂O + 0₂
yes
no
Which units are used to measure both velocity and speed? Select three options.
m/s
d/t
km/h
mph
lph
Answer:
m/s
km/h
mph
Explanation:
speed is measured with distance which does in velocity too that is why I chose this answer
Which statement describes a chemical property related to the
particles that make up the material?
O
A. Magnesium oxide crystals are hard and brittle because
they are made up of atoms that combine by ionic bonding.
O B. Iron is a good conductor of electricity because the metallic
bonds between its atoms allow electrons to move freely.
O c. Aluminum has a relatively low density because its atoms
have fewer protons than the atoms of most other metals.
O D. Aluminum is relatively inert because its atoms do not react
readily with molecules in the atmosphere.
Iron is a good conductor of electricity because the metallic bonds between its atoms allow electrons to move freely.
What is Chemical property?These are the features which can be observed when the substance undergoes a chemical reaction.
Good conductor of electricity is a chemical property and is common among metals as a result of the metallic bonds which is why option B was chosen.
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3. Two wires increase in length by the same amount when both their temperatures increase by the same amount, as shown in the diagram. Before the temperature increase, the longer wire is 1.2525 m long. The shorter wire’s linear coefficient of thermal expansion is 1.135 times that of the longer wire. How much shorter is the shorter wire before the temperature increase? Answer to three significant figures
Viết cho Ngọc Khánh
Two wires increase in length by the same amount when both their temperatures increase by the same amount, the shortness of the wire before the temperature increase is mathematically given as
dL=0.1485m
How much shorter is the shorter wire before the temperature increase?Generally, the equation for change in length is mathematically given as
[tex]dl=lo \alpha dt[/tex]
Therefore
dl1=dl2
Where
a2=1.35a1
Hence
a1l1dt= a2l2dt
a1(1.2525)= a1*(1.135)(l2)
L2=1.104m
In conclusion, a change in length due to temperature is
dL=1.2525-1.104m
dL=0.1485m
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at what temperature does the fahrenheit scale read quartered the celsius scale ? what is the corresponding reading in kelvin scale ?
The temperature at which the Fahrenheit scale reads quartered the celsius scale is : -5.16 ⁰F, -20.64⁰C
Reading in kelvin scale = 252.5 K
Determine the temperature at which the Fahrenheit scale reads quartered the celsius scaleThe relationship between Fahrenheit and celsius can be expressed as
F = (9/5)(C) + 32 ---- ( 1 )
Therefore the temperature at which Fahrenheit scale quarters the celsius scale is :
F = 1/4 C --- ( 2 )
Back to equation ( 1 )
1/4 C = (9/5)(C) + 32
1/4C - 9/5C = 32
C ( 1/4 - 9/5 ) = 32
C = 32 / ( 1/4 - 9/5 )
= -20.64⁰C
F = 1/4 ( -20.64 ) = -5.16 ⁰F
Hence we can conclude that The temperature at which the Fahrenheit scale reads quartered the celsius scale is : -5.16 ⁰F, -20.64⁰C. Reading in kelvin scale = 252.5 K
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CFCs were found to destroy what important compound in our atmosphere?
CFCs were found to destroy the important compound in our atmosphere which is called as the Ozone layer.
What are CFCs?The CFCs are called as the Chloro Fluoro carbon are the fuels used in the jet flights long time ago.
The ozone layer protects the harmful UV rays coming from the Sun to reach the Earth's surface. This layer was depleted by the use of CFCs which consist of harmful element Chlorine in large amount.
This has developed a hole in ozone layer over Antarctica. Global warming is the greatest consequence of the depletion of ozone layer.
Thus, CFCs found to destroy ozone layer.
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Which is the smallest unit of life?
Answer:
the cell is the smallest unit
Discuss how wind energy was used in ancient times.
Answer:
People used wind energy to propel boats along the Nile River as early as 5,000 BC. By 200 BC, simple wind-powered water pumps were used in China, and windmills with woven-reed blades were grinding grain in Persia and the Middle East.
Explanation:
Hope it helps you:)))))
have a good day
food does not pass through the liver or the pancreas why are these organs dtill important parts of the digestive system?
Your pancreas makes a digestive juice that has enzymes that break down carbohydrates, fats, and proteins. The pancreas delivers the digestive juice to the small intestine through small tubes called ducts. Liver. Your liver makes a digestive juice called bile that helps digest fats and some vitamins.
Digestive enzymes are made by the pancreas and aid in the breakdown of proteins, carbs, and lipids. Bile, a liquid made by the liver that aids in fat digestion, is produced.
What is meant by digestive system ?The digestive system breaks down the food we consume into its most basic components, such as glucose (sugar), amino acids (which make up protein), or fatty acids (which make up lipids).
Here,
The digestive system of humans is made up of a fully formed alimentary canal and the glands that are located there. The alimentary canal, which includes the mouth, oral cavity or buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine, and anus, is encircled by glandular epithelium.
The nutrients from the digested food are subsequently transported to every cell in the body thanks to absorption into the bloodstream from the small intestine.
Although they are not a part of the alimentary canal, the pancreas, which is located beneath the stomach, the gallbladder, and the liver are all vital for digestion.
Hence,
Digestive enzymes are made by the pancreas and aid in the breakdown of proteins, carbs, and lipids. Bile, a liquid made by the liver that aids in fat digestion, is produced.
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Mr smith needs to put the paving stone dosnt to rest his arms. He does not want the paving stone to sink deep into the mud . Explain which surface of the stone he should put on the ground.
The surface of the stone which he should put on the ground is the base.
What is a Base?This is defined as the flat end which is usually located at the bottom with a larger surface area.
The large surface area helps to distribute the forces on all parts thereby preventing it from sinking.
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Why is digital forensics important?
Hi! digital forensics is important because not only does digital forensics allow cyber security organisations to develop technologies that can prevent hackers from accessing devices, websites and networks but can lead businesses in the direction of understanding exactly what data is compromised.