Answers
Answer:
Heat lost thru doors & windows = (100 - 75 - 5) = 20
20% is the fraction of heat lost thru doors and windows
One wants to obtain the largest savings per unit of cost
roof:
200 / 600 = 1/3
150 / 1000 = .15
40 / 2300 = .017
The largest of these is 1/3 so the most benefit would be obtained by insulating the roof
Since heat loss thru the roof depends on heat loss thru the attic, this is the most cost effective in reducing heat loss
The more the difference in temperature between the ceiling and roof (attic) the more heat will be lost thru the roof, so insulating the roof will decrease the heat loss of the attic
Related Questions
Which of these is an example of Newton’s first law of motion?
A. A basketball bounces on the ground with the same force that the ground pushes up on the ball.
B. A person standing on a bus moves backward when the bus suddenly moves forward.
C. A person jumps to a dock from a boat, and the boat moves away from the dock.
D. A baseball hit with a baseball bat travels faster than a bowling ball hit with the same force
Answers
Answer:
a baseball hit with a baseball bat travels faster than a bowling ball hit with the same type of force
Explanation:
In which direction is there a net force of 200 N?
Coordinate plane with top and bottom of x axis labeled 300 N and left side of y axis labeled 200 N and right side labeled 400 N with a point marked closer left of center
Question 2 options:
left
right
up
down
Answers
Answer:
right
Explanation:
The up and down forces cancel
then you are left with a -200 and a + 400
resulting in a + 200 (to the right)
A person on a bicycle travels a distance of 12.5 km in 2.1 hrs, what was the speed of the person on the bicycle?
Answers
Answer:
5.9 km/hour
Explanation:
divide 12.5 by 2.1 and the answer is 5.9
Fuses protect electrical devices by opening a circuit if the current in the circuit is too high. Would a fuse work successfully if it were connected in parallel with the device that it is supposed to protect
Answers
A fuse is placed in parallel with the device it is supposed to protect will not work successfully.
Meaning of a fuse and how it worksA fuse is an electrical and electronics device that protects a system from excess current. it breaks to deter the flow of current into a device.
The work of a fuse is important to every electrical circuit and device.
A fuse is always in series with the device its to protect, so it can easily break of and by so doing current will not flow to the device again.
In conclusion if a fuse is placed in parallel with the device it is supposed to protect, it will not work successfully.
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2. Three identical lamps are connected in
series with each other. If the resistance
of each lamp is X ohms, what is the
equivalent resistance of this series
combination?
(1) ΧΩ
(3) 3X22
(2) 2
2
(4) 2
w/
X
Answers
The equivalent resistance of the series combination is : 3XΩ
Determine the Equivalent ResistanceEquivalent Resistance is the total resistance in circuit (i.e parallel or series circuits).
Bulb in series have the same resistance. Therefore each Bulb has a resistance of XΩ
equivalent resistance = [tex]R_{1}[/tex] + [tex]R_{2}[/tex] + [tex]R_{3}[/tex]
Let [tex]R_{1}[/tex] represent resistance of bulb one
[tex]R_{2}[/tex] represent resistance of bulb two
[tex]R_{3}[/tex] represent resistance of bulb three
equivalent resistance = X + X + X
equivalent resistance = 3XΩ
In conclusion, the equivalent resistance of the series combination of Three identical lamps connected in series with each other with a resistance of X ohms each is 3XΩ
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A greenhouse is an example of a(n) __________________________________. Question 7 options: active solar energy system. biomass generator. passive solar energy system. nonrenewable energy source.
Answers
What would decrease the efficiency of this truck?
A. Keep the truck well-oiled.
B. Change the oil frequency.
C. Take off the brake pads.
Please help!!
Answers
Answer: The answer isC .
Explanation:
Keeping the truck well oiled increases it.
Changing the oil frequency depends on the truck and oil but still doing it increased and helps the truck.
Taking off the breaks pads would decrease the truck, based on how the answer options is written the answer is C because your not changing them but taking them off.
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A metal block has a mass of 5 grams and a volume of 1 cm3. What is the density of a piece of the same identical metal but with a different shape and different volume
Answers
Answer:
ρ = Mass / Volume definition of density
ρ = 5 g / 1cm^3 = 5 g / cm^3
Since the other object is made of the same metal its density is the same:
ρ = 5 g/cm^3
The density of a piece of the same identical metal but with a different shape and different volume is [tex]\rho = 5 g/cm^3[/tex].
What is density?The density of a substance is its mass per unit volume. Density gives information about how tightly the substance is packed together. The formula for density is
[tex]\rho ={\frac {m}{V}}[/tex]
Unit of density is grams per cubic centimetre.
What are uses of density?One of the most common uses of density is in how different materials interact when mixed together.Wood floats on water because it has a lower density than water, while an anchor sinks as the metal has high density.Balloons filled with helium gas float because the density of the helium is low than the density of air.Given:
Mass, [tex]m = 5 g[/tex]
Volume, [tex]V = 1 cm^{3}[/tex]
The density of metal is
[tex]\rho = \frac{5}{1}\\ \\\rho = 5 g/cm^{3}[/tex]
Since, the other object is made of the same metal. So, density is the same.
[tex]\rho = 5 g/cm^3[/tex]
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Without telescopes or other aid, we can look up and see the moon in the night sky because it.
Answers
Answer:
because the moon is nearer to the earth compared to the stars which we require telescopes to observe
Suppose that a college physics experiment goes horribly wrong and releases an electronic pulse that renders all electronic equipment in the cities of columbus, cleveland and cincinnati, ohio permanently useless. No people are hurt, and no buildings are damaged. After the accident, the wages earned by ohio workers will.
Answers
Answer:
It will decrease because the marginal productivities of workers will decrease. Diminishing marginal product occurs when the marginal product of an input goes down as the quantity of the input goes up. The transformation in product resulting from employing one more unit of a particular input for instance, the change in output when a firm's labor is mark up from five to six units, assuming that the mass of other product are kept constant is called The input of marginal product or marginal physical product.
Explanation:
How much will stretch a spring that has spring constant of 735 N/m, if you vertically hung a 2. 30 kg object from it. How much work must an external agent do to stretch the same spring 6. 50 cm from its unstretched position?
Answers
Answer:
Part 1 = 0.03m, Part 2 = 1.4651J
Answer:
F = - K X
X = -F / K = M g / K = 9.8 * 2.3 / 735 = .03 m = 3 cm
W = 1/2 K X^2
W = 1/2 * 735 N/m * .065^2 m^2 = 1.55 Joules
Second and third class levers are differentiated by __________. a. the location of the fulcrum b. the location of the load c. the presence of multiple loads d. the type of fulcrum present please select the best answer from the choices provided. a b c d
Answers
Answer:
Its B
Explanation:
Its B because i said its B alright cool bet
Second and third class levers are differentiated by the location of the load. The correct option is b.
The position of the weight in relation to the fulcrum distinguishes second-class levers from third-class levers.
The load is situated in a second-class lever halfway between the fulcrum and the applied force. The effort is placed between the fulcrum and the load in a third-class lever.
The mechanical advantage and the way these levers magnify force or motion depend on where the load is placed in relation to the fulcrum.
Thus, the correct option is b.
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Distant galaxies we can see today with a redshift of z >> 6 emitted their light when the universe was:
Answers
Distant galaxies we can see today with a redshift of z >> 6 emitted their light when the universe was expanding.
What is a Galaxy?This term comprises of stars and interstellar matter that make up the universe.
, The farther a galaxy, the faster it is receding from Earth which depicts its expansion and makes it the most appropriate choice.
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How will you describe the horizontal and vertical motions of a projectile?
Answers
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3. Give an example of a mechanical wave that changes frequency.
Answers
Answer:
No , impossible
Explanation:
Mechanical waves are those waves which requires a medium to travel through. for example sound ,if you put a speaker inside vaccum you can't hear it .As they changes their medium their wavelength is changed but frequency remains sameWhat property of matter is most responsible for the fact that sound travels at different speeds through different materials?.
Answers
Answer:
density
Explanation:
higher density ===> higher propagation speed
describe the friction of smooth surfaces
Answers
When two surfaces slide against each other, a force called friction makes them stick very slightly together. Smooth surfaces, like ice and glass, are easy to slide over. They create very little friction. Rough surfaces like rock and sand create much more friction, and are easy to grip on to.
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When we say charge is conserved, we mainly mean that charge can be _________. View Available Hint(s)for Part A constant in all bodies transferred without loss like money in a bank created and destroyed in equal amounts saved, like money in a bank
Answers
Answer:
neither created nor destroyed.
Explanation:
Describe how a speed-time graph shows an object that is stationary
Answers
Answer:
When in the graph the line is horizontal it states that the moving object is stationary
Explanation:
The slope of a speed-time linear graph is NOT_____.
acceleration
direction
Answers
Answer:
direction
Explanation:
the slope of a velocity time graph is the acceleration
A twin-sized air mattress used for camping has dimensions of 100 cm by 200 cm by 15 cm when blown up. The weight of the mattress is 2 kg. How heavy a person could the air mattress hold if it is placed in freshwater
Answers
For a twin-sized air mattress used for camping has dimensions of 100 cm by 200 cm by 15 cm when blown up, the weight is mathematically given as
M=2923.38N
What is the weight of a person could the air mattress hold if it is placed in freshwater?Generally, the equation for the maximum mass is mathematically given as
M=Vp-m
Therefore
M=100*200*15(1*10^3)-2kg
M=298kg
In conclusion, the weight
W=298kg*9.81
W=2923.38N
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Two coils connected in series have a resistance of 36 ohm and when connected in parallel have a resistance of 8ohm. Find resistance of each coil
Answers
Answer:
Explanation:
Remark
Two resistances in series has the form of
Rs= C1 + C2
Two resistances is parallel has the form of
Rp = (C1 *C2)/(C1 + C2)
The plan is to first of all find C1*C2 and use this information and C1 + C2 to find the individual resistances.
Givens
Rs = 36 ohms
Rp = 8 ohms
Solution
Rp = C1 * C2/(C1 + C2)
Rp = 8 ohms
C1 + C2 = 36 ohms
8 = C1*C2 / 36 Multiply by 36
8* 36 = C1*C2
C1*C2 = 288
Use Rs to solve for C1
C1 + C2 = 36C1 = 36 - C2(36 - C2) * C2 = 288
36*C2 - C2^2 =288 Multiply by - 1
-36C2 + C2^2 = -288 Add 288 to both sides
C2^2 - 36C2 + 288= 0 Factor this equation
(C2 - 12)(C2 - 24)
C2 - 12 = 0
C2 = 12
C2 - 24 = 0
C2 = 24
C2 = 24 or
C2 = 12
C1 = 36 - C2
C1 = 36 - 24 = 12
C1 = 36 - 12 = 24
Answer
C1 = 12 ohms or 24 ohms
C2 = 24 ohms or 12 ohms
An ant is crawling up a leaf that is hangin vertically. it lifts 0:007 kg crumb up 0:12 meters. to do this, the ant exerts 0.069 newtons of force. how much work dis the ant do on the crumb?
Answers
Answer:
.000828 j
Explanation:
Work = F * d
.0069 N * .12 m = .000828 j
How long does it take light to travel from jupiter to earth?.
Answers
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Collisions between galaxies are rare and have little or no effect on the stars and interstellar gas in the galaxies involved. true or false
Answers
Answer:
false
Explanation:
A lamp is marked 24V, 100W. Describe an experiment to check that the electrical power supplied to the lamp is 100W when the p.d. across it is 24V.
In your account you should
* include a circuit diagram,
* state the readings that are taken,
* show how the result is calculated from the readings.
Answers
The electrical power supplied to the lamp is 100W when the p.d. across it is 24V and the current is 4.2 A.
What is electrical power?Electrical power is the rate at which electrical work is done.
The unit of electrical power is Watts.
Power = Current × VoltageThe experiment will require a 24V Battery, a Lamp marked 24V, 100 W, a key, wires, a rheostat, a voltmeter and an ammeter.
The circuit is completed and the rheostat is adjusted to provide until the voltmeter reads 24V.
The ammeter reading is taken as well.
When the voltmeter reading is 24V, it can be seen that' the ammeter reading for current is approximately 4.2 A.
Calculating, the power of the lamp:
Power = 24 × 4.2 = 100 W
Therefore, the electrical power supplied to the lamp is 100W when the p.d. across it is 24V and the current is 4.2 A.
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one particular descent goes from 2100m to 1600m. Assuming work done against friction is 90% of the potential energy change of the cyclist and the cycle, what increase in speed in Km/h can a rider attain by the end of the
descent?
Answers
Answer:
1/2 M V^2 = .1 M g H where 10% of PE goes into KE
V^2 = .2 g H = .2 * 9.8 * (2100 - 1600) = 980 m^2 / s^2
V = 31.1 m/s increase in speed during descent
1 km / hr = 1000 m / 3600 sec = .278 m/s
V = 31.1 m/s / (.278 m/s / km /hr)= 112 km/hr
A –0.06 c charge is placed is in a uniform electric field with a strength of 200 n/c. what is the magnitude and direction of the force on the charge? 12 n in the opposite direction of the field 12 n in the same direction of the field 3333 n up in the opposite direction of the field 3333 n in the same direction of the field
Answers
The magnitude of the charge is 12 N in the opposite direction of the field.
What is Electric field?The term electric field refers to the region in space where the effect of a charge is felt. In this case, we are told that the magnitude of the charge is –0.06 C.
Hence;
E = F/q
F = Eq
F = –0.06 C * 200 N/C
F = 12 N
Hence, the magnitude of the charge is 12 N in the opposite direction of the field.
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Answer:
A
Explanation:
Edge
How does the atmospheric temperature and size of inner planets compare with those of outer planets?
Answers
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_____ is a device
which increases or decreases voltage.
Iron
core
Electricity Primary
Coil
(input)
Secondary Electricity
Coil
in
out
(output)
100 V
10 A
1000 W
static charge
charges
transformer
force field
Primary
55 turns
Secondary
20 turns
Core
400 V
2.5 A
1000 W
Answers
Answer:
transformers
Explanation:
A transformer is a device that increases or decreases voltage.