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2 years ago

I would really appreciate the help on this pass paper question.

Physics

1 answer:

zvonat [6]2 years ago

8 0

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

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It has been suggested that a heat engine could be developed that made use of the fact that the temperature several hundred meter

lesantik [10]

Answer:

efficiency = 5.4%

Explanation:

Efficiency of heat engine is given as

$\eta = \frac{W}{Q_{in}}$

now we will have

$W = Q_1 - Q_2$

so we will have

$\eta = 1 - \frac{Q_2}{Q_1}$

now we know that

$\frac{Q_2}{Q_1} = \frac{T_2}{T_1}$

so we have

$\eta = 1 - \frac{T_2}{T_1}$

$\eta = 1 - \frac{273+6}{273+22}$

$\eta = 0.054$

so efficiency is 5.4%

8 0

3 years ago

What is the Isotope notation for a Lithium atom?

Serggg [28]

Lithium has five isotopes, and each will have different notation. Lithium-7 is commonly used in salt and nuclear reactors. .ZAX , where X is the atomic symbol for the element, here Li for lithium, Z is the mass number, or the total number of protons and neutrons, and A is the atomic number, or the number of protons

6 0

3 years ago

A ray diagram without the produced image is shown.

4vir4ik [10]

A car acting as an object in front of a biconvex lens between F and 2 F on the object side of the lens. There is a light ray parallel to the principal axis that is bent through F on the image side of the lens. There is a ray straight through the center of the lens. The rays intersect below the x axis further than 2 F away from the lens and farther from the principal axis than the object is tall.

<u> The image produced by the lens is (b) inverted and real</u>

Explanation:

A real image occurs where the rays converge.

Real images can be produced both by the concave mirrors or converging lenses, but the condition is that the object of consideration is always placed far away from the mirror or the lens than the focal point, and thus the real image produced is inverted.

<u> The image produced by the lens is (b) inverted and real</u>

8 0

3 years ago

When the moon slowly moves away from the earth.How is it affecting the gravitational force between the earth and the moon?

sukhopar [10]

Well, think about how the tides will be affected when the moon moves farther away. If the moon first started off very close the earth, we would have more tsunamis. (Scientists have found that the moon has possibly been closer to earth long ago.) While it moves away, soon there will no longer be many tides.

3 0

3 years ago

A crate required 900 newtons (N) of force to lift. The crate was lifted by a forklift with an engine that provided 225 N of forc

Alenkinab [10]

The mechanical advantage of the forklift is calculated to be 4.

<h3>MECHANICAL ADVANTAGE:</h3>

The mechanical advantage of a machine can be calculated by dividing the load (F) by effort (F). That is;

M.A = Load/Effort

According to this question, a crate required 900 newtons (N) of force to lift. The crate was lifted by a forklift with an engine that provided 225 N of force. The mechanical advantage is calculated as follows:

M.A = 900N ÷ 225N

M.A = 4.

Therefore, the mechanical advantage of the forklift is calculated to be 4.

Learn more about mechanical advantage at: brainly.com/question/10221970

6 0

3 years ago