Answer:
71 % eff
Explanation:
if 50 out of 70 watt goes to making light
50/70 = 71 %
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Which of the following predictions is likely to be correct?
A
If it is August, shadows will soon be longer.
B
If it is March, shadows will soon be longer.
C
If it is September, shadows will soon be shorter.
D
No matter what time of year it is, shadows will remain the same.
Answer:
D
No matter what time of year it is, shadows will remain the same.
Explanation:
Answer:
A
Explanation:
Late in the year the sun the earth is tilted away from the sun that means the sunlight is not coming in as directly. So, shadows during are longer.
Why is glass a good insulator?(1 point)
Explanation:
Glass is good insulator because of the following reason:
It is poor conductor of heat and electricityIt doesn't allow the flow of current/electron between two atoms, ions or species.It can be easily prepared in industries.It is eco friendly, It does not lead to deforestation like wooden insulator does, and doesn't harm/pollute the environment like rubber and plastic insulator does.It can be used upto high temperature level because it have high melting point (1700°C)Thanks for joining brainly community!
Glass is considered a good insulator because of its special way its molecules are arranged and its properties.
Why is glass a good insulator?Glass is not like other solid materials because it doesn't have a regular structure. This messy pattern of atoms in glass makes lots of tiny holes and dirt in the material. Air bubbles and dirt make it harder for heat to move through the glass, so less heat moves through it.
Glass doesn't transfer heat easily because it has low thermal conductivity. Glass does not allow heat to move through it easily and helps to keep heat inside.
Glass does not easily let electricity pass through it. This means that it doesn't let electricity pass through easily. Glass cannot conduct electricity because it does not have any free electrons or mobile charged particles.
Glass allows infrared radiation, which is a type of heat energy, to pass through it. Glass lets light in but stops some heat from getting through.
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Choose the clincher sentence that best restates the following topic sentence.
Scientists recently discovered that fun is not just fun; it's
good for the brain.
O A. Not having fun can be bad for the brain.
O B. Fun is definitely good for the brain!
O C. Sometimes, you can have too much fun for the brain to process.
O D. A fun activity like horseback riding can actually make the brain
smarter.
Which law represents a balanced chemical equation? A. Avogadro’s hypothesis B. ideal gas law C. law of conservation of mass D. Newton’s first law of motion E. Newton’s second law of motion
Is it possible for a person to have zero mechanical energy?
Answer:
no
Explanation:
Design a hypothetical structure to be used as a 500,000 square-foot office space in Los Angeles, California. Create a drawing with labels for dimensions and describe any specifications for materials and other features that will add to its structural integrity in the event of a typical earthquake event in that area. Incorporate at least three features to help maintain the building’s structural integrity during an earthquake. Describe how each feature will improve the building’s earthquake resistance
To design an earthquake-resistant structure, we must take several aspects into account, such as materials and construction techniques.
What is an earthquake resistant structure?An earthquake-resistant structure is a term that refers to a type of structure that has the characteristic of resisting earthquakes without being destroyed or seriously affected.
Earthquake-resistant structures were developed to prevent tragedies due to the collapse of structures during earthquakes. Generally, to make a structure earthquake resistant, materials are used that resist the movements of the earth without breaking.
The most used materials to make earthquake-resistant structures are:
WoodConcreteBricksMetals (iron, steel, others)Among others.Additionally, earthquake-resistant structures include specific construction techniques that allow them to arrange materials in a certain way to resist movement.
According to the above, the best option to build a 500 square foot earthquake-resistant structure is a 25-foot-wide by 20-foot-long single-story structure to make it more resistant to earth movements.
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chemical process where a solid turns into a gas without going through a liquid stage.
(A) witchcraft
(B) sublimation
(C) potential phase
Answer:
B) sublimation
Explanation:
An example is the vaporization of frozen carbon dioxide (dry ice) at ordinary atmospheric pressure and temperature.
Answer:
sublimation
Explanation:
sublimation, in physics, conversion of a substance from the solid to the gaseous state without its becoming liquid. An example is the vaporization of frozen carbon dioxide or dry ice(CO2)
or Solid Chlorine (Cl2) at ordinary atmospheric pressure and temperature. The phenomenon is the result of vapour pressure and
temperature relationships.
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Which situation results in no work being done?
O lifting an object off the ground
O throwing a baseball to your friend
O carrying a book at a constant velocity
O pushing a car that will not start out of the garage
Answer:
C
Explanation:
C should be the right answer
What is the frequency of a wave that has a period of 5 seconds
Answer:
0.20 Hz
Explanation:
Frequency is the reciprocal of the period. The period is 5 seconds, so the frequency is 1/(5 s) = 0.20 Hz.
A lever where the input force is between the fulcrum and the output force (a broom) is what type of lever?
Answer:
first class lever
in a first class lever fulcrum is b/w input and output force
What is the name for a supporting force that acts upward and in a direction perpendicular to a surface
What is the wasted energy in each of the energy transfers?
a) clockwork toy
b) boy kicking a football
c) boiling kettle on a gas ring
d) person walking upstairs
Answer:
a person walking upstairs is a wasted energy
Define the following words:
Phylogenetic:
Bifurcation:
Taxonomy:
Prokaryote:
Eukaryote:
Virus:
Classification:
Biotype:
(brainliest if you use your own words) please hurry!!!
Not all metals have the same current for a given electric potential
The statement 'Not all metals have the same current for a given electric potential' is TRUE. It is conductivity.
What is conductivity?All the metals are able to conduct electric currents, but some metals have a higher conductivity.
Metals are able to conduct electric currents due to the free movement of negatively charged particles i.e., electrons, across the conductor.
The band theory of metals states that metals can conduct electrons (e-) in an electric current by means of the help of the e- valence.
The density of free electrons in metals is around 10^28 m-3, which indicates the number of states at a particular energy level that negative e- can occupy.
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The dimensions of a triangle are shown below.
What is the area of the triangle?
Answer:
7. answered because ia an pro
Explanation:
[tex]area = \frac{1}{2} bh[/tex]
[tex]area = \frac{1}{2} \times 60 \times 50[/tex]
[tex]area = \frac{3000}{2} [/tex]
[tex]area = 1500mm ^{2} [/tex]
what type of matter is always made up of only one kind of atom
A flywheel is rotating with an angular velocity of 1.4 rad/s and is acted on by an acceleration of 0.6 rad/s².
a) What angular velocity will it have attained after three complete turns?
b) How long will it take to do those three turns?
(a) The final angular velocity of the flywheel after 3 complete revolutions is 4.96 rad/s.
(b) The time taken for the flywheel to make 3 complete revolutions is 5.93 s.
Final angular velocityThe final angular velocity of the flywheel after 3 complete revolutions is determined by applying third kinematic equation as shown below;
θ = 2π (rad/rev) x (3 rev) = 18.85 rad
ωf² = ωi² + 2αθ
ωf² = (1.4)² + 2(0.6)(18.85)
ωf² = 24.58
ωf = √24.58
ωf = 4.96 rad/s
Time of motionThe time taken for the flywheel to make 3 complete revolutions is calculated as follows;
ωf = ωi + αt
t = (ωf - ωi)/α
t = (4.96 - 1.4)/0.6
t = 5.93 s
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calculate the kinetic energy of a 71 kg man running at 5 m/s
Answer:
887.5 J
Explanation:
Kinetic energy is the energy gained by a body due to its motion.
Its formula is :-
KE = [tex]\frac{1}{2} mv^{2}[/tex]
m = massv = velocityValues we are given :
m = 71 kgv = 5 m/sSubstituting :
KE = 1/2 x 71 x 5²KE = 35.5 x 25KE = 887.5 JTwo pulses are moving along a string. one pulse is moving to the right and the second is moving to the left. both pulses reach point p at the same instant. an illustration with a rectangular crest moving toward the right and a triangular trough going toward the left both toward point p and equidistant from p. which diagram shows the appearance of the string after the pulses pass point p? an illustration with the triangular trough in the middle of the rectangular crest to the left of point p. an illustration with the triangular trough in the middle of the rectangular crest to the right of point p. an illustration with a rectangular crest moving toward the right past p and a triangular trough going toward the left past p. an illustration with a rectangular crest moving toward the left and a triangular trough going toward the right both away from point p and equidistant from p.
The two pulses will have Constructive interference. Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes.
What is constructive interference?
Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes. Equivalently, the minima of the waves would be aligned
This is an example of a standing wave produced when two ends of a string are oscillated in the same plane. The displacement of of point on two ends oscillates vertically.
We are given that two pulses move along the string each coming towards each other and meet at a common point ( P ).
Each pulse have their own magnitude or displacement in the vertical plane. If the pulses are to meet at a common point at the same instant, then they interfere with each other constructively.
Where constructive interference of two pulses is the addition of magnitudes of induvidual pulses and form a single puls of the constructed magnitude.
magnitude ( New pulse ) = magnitude (Pulse 1) + magnitude (Pulse 2)
Hence the two pulses will have Constructive interference
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Answer:
C
Explanation:
edge 22
which of the following states statements are true
1 sound travel faster in high temperature 2 sound travel slower in cold air i than Hot air
A car is traveling on the road at a velocity (Vx) of 35m/s. A person in the passenger seat
has a tennis ball and is tossing the ball up in the air to himself. He throws the ball directly up
with a velocity (Vy) of 3m/s. An outside observer is sitting on a bench on the side of the street
watching the car pass.
a) To the person inside the car, the ball travels directly up and down. But to the
outside observer, what is the launch angle of the ball?
b) What is the ACTUAL Speed (IVI) of the ball when it leaves the person's hand?
c) What is the maximum height the ball will reach in the car?
d) How long will the ball stay in the air?
e) How far will the ball travel in the direction of travel on the road?
(a) The launch angle of the ball is 5⁰.
(b) The actual speed of the ball when it leaves the person's hand is 35.13 m/s.
(c) The maximum height reached by the ball is 0.46 m.
(d) The time spent in air by the ball is 0.26 s.
(e) The horizontal distance traveled by the ball on the road is 4.55 m.
Launch angle of the ball
The launch angle of the ball is calculated as follows;
[tex]tan(\theta) = \frac{V_y}{V_x} \\\\\theta = tan^{-1} (\frac{3}{35} )\\\\\theta = 5\ ^0[/tex]
Actual speed of the ballThe actual speed of the ball when it leaves the person's hand is calculated as follows;
[tex]V = \sqrt{V_x^2 + V_y^2} \\\\V = \sqrt{(35)^2 + (3)^2} \\\\V = 35.13 \ m/s[/tex]
The maximum height reached by the ballThe maximum height reached by the ball is calulated as follows;
[tex]Vy_f^2 = V_y_i^2 - 2gh\\\\0 = 3^2 - 2(9.8)(h)\\\\19.6h = 9\\\\h = \frac{9}{19.6} \\\\h = 0.46 \ m[/tex]
Time spent in air by the ballThe time spent in air by the ball is calculated as follows;
[tex]h=V_yt + \frac{1}{2} gt^2\\\\0.46 = 3t + 4.9t^2\\\\4.9t^2 +3t - 0.46 = 0\\\\a = 4.9, \ b = 3, \ c =- 0.46\\\\t = \frac{-b \ \pm \ \sqrt{b^2 - 4ac} }{2a} \\\\t = 0.13 \ s[/tex]
Total time for upward and downward motion = 2(0.13 s) = 0.26 s
Horizontal distance traveled by the ballX = Vx(t)
X = 35 x 0.13
X = 4.55 m
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Lake point tower in chicago is the tallest apartment building in the united states. suppose you take the elevator from street level to the roof of the building. the elevator moves almost the entire distance at constant speed, so that it does 1.15x10^5j of work on you as it lifts the entire distance. if your mass is 60.0 kg how tall is the building.
Using the idea of work done under gravity, the height of the building is 187 m.
Work done in a gravitational fieldWe must recall that the work done in a gravitational field is given by; mgh
m= mass
g = acceleration due to gravity
h = height
mass = 60.0 kg
Workdone = 1.15x10^5 J
W = mgh
h = W/mg
h = 1.15x10^5 J/60.0 kg * 9.8 ms-2
h = 187 m
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White light is sent through glass prism. Which color is refracted the most?.
tyfg bh nbv gf ddd ds
Answer:
..........................................................
Explanation:
A car of mass 10.0 ks traveling at 5.00 m/s comes to rest due to friction after traveling 20.0 m. What is the work done on the car by the friction?
A. –125 J
B. –50 J
C. 50 J
D. 125 J
The work done on the car due to friction is -125 J.
What is workdone?Work is said to be done when a force moves an object through a certain distance.
To calculate the workdone on the car by friction, we use the formula below
Formula:
W = m(v²-u²)/2.......... Equation 1
Where:
W = Work done due to fricionm = mass of the carv = Final velocityu = Initial velocityFrom the question,
Given:
m = 10 kgv = 0 m/su = 5 m/sSubstitute these values into equation 1
W = 10(0²-5²)/2W = 5(-25)W = -125 JHence, The work done on the car due to friction is -125 J.
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A scuba diver uses his waterproof flashlight to shine a beam of light so that it strikes the surface of the water at an angle of incidence . Use Snell’s law to find the angle of incidence that would give an angle of refraction for the refracted ray to be directed right along the surface, and show that is the same as the critical angle for total internal reflection.
Answer:
the light speed up and change it directtions
A tank contains compressed air at 5 ATM. What is the pressure in pascals?
Answer:
1 atm = 1.01E5 nt/m^2 = 1.01E5 pascals
5.05E5 nt/m^2 = 5.05E5 pascals
1 pascal = 1 nt/m^2
What do sunspots, solar prominences, and solar flares all have in common?.
a fan rotate with a speed of 450rev/min after switch off it comes to rest in 10 second assuming constant angular acceleration ,calculate the number of revolution made by it before coming to rest
Here; f = 450 rev/ min = 450/60 rev/s
f. = 15/2 rev/s
Therefore the angular velocity w. = 2π f•
= 15π rad / sec at t= 10s, w = 0
Therefore Angular acceleration
a=w-w./t
= w + 1/2 at^2
= 15π * 10 - 1/2 (3π/2) 10^2
= 150-75m = 75π rad
Therefore No. of revolution = •/2π = 75/ 2π
= 37.5