ENGINEERING COLLEGE

A wall in a house contains a single window. The window consists of a single pane of glass whose area is 0.15 m2 and whose thickness is 5 mm. Treat the wall as a slab of the insulating material Styrofoam whose area and thickness are 10 m2 and 0.15 m, respectively. Heat is lost via conduction through the wall and the window. The temperature difference between the inside and outside is the same for the wall and the window. Of the total heat lost by the wall and the window, what is the percentage lost by the window

Answers

Answer 1

Answer:

Answer:

The percentage loss of the window is $E = 97.3$ %

Explanation:

From the question we are told that

The area of pane of glass is $A = 0.15 m^2$

The thickness is $d = 5mm = (5)/(1000) = 0.005m$

The thickness of the wall is $D = 0.15m$

The area of the wall is $a = 10m^2$

Generally the heat lost as a result of conduction of the window is

$Q_(window) = (j_(glass) * A * (\Delta T) )/(d)$

Where $j_(glass)$ is the thermal conductivity of glass which has a constant value of

$j_(glass) = 0.80 J/(s \cdot m \cdot C^o)$

Substituting values

$Q_(window) = ( 0.80 * 0.15 * (\Delta T) )/(0.005)$

$Q_(window) = 24 \Delta T$

Generally the heat lost as a result of conduction of the wall is

$Q_(wall) = (j_(styrofoam) * A * (\Delta T) )/(d)$

$j_(styrofoam)$ s the thermal conductivity of Styrofoam which has a constant value of $j_(styrofoam) = 0.010J / (s \cdot m \cdot C^o)$

Substituting values

$Q_(wall) = ( 0.010 * 10 * (\Delta T) )/(0.15)$

$Q_(wall) = 0.667 \ \Delta T$

Now the net loss of heat is

$Q_(net) = Q_(window) + Q_(wall)$

Substituting values

$Q_(net) = 24 + 0.667$

$Q_(net) = 24.667$

Now the percentage loss by the window is

$E = (Q_(window) )/(Q_(net)) * 100$

Substituting value

$E = (24)/(24 .667) * 100$

$E = 97.3$ %

Related Questions

A tensile test is carried out on a bar of mild steel of diameter 20 mm. The bar yields under a load of 80 kN. It reaches a maximum load of 150 kN, and breaks finally at a load of 70 kN. Find (i) the tensile stress at the yield point (1i) the ultimate tensile stress; (iii) the average stress at the breaking point, if the diameter of the fractured neck is 10mm
What regulations is OSHA cover under what act
8.2.1: Function pass by reference: Transforming coordinates. Define a function CoordTransform() that transforms the function's first two input parameters xVal and yVal into two output parameters xValNew and yValNew. The function returns void. The transformation is new
An aquifer has three different formations. Formation A has a thickness of 8.0 m and hydraulic conductivity of 25.0 m/d. Formation B has a thickness of 2.0 m and a conductivity of 142 m/d. Formation C has a thickness of 34 m and a conductivity of 40 m/d. Assume that each formation is isotropic and homogeneous. Compute both the overall horizontal and vertical conductivities.
Determine the voltage across a 2-μF capacitor if the current through it is i(t) = 3e−6000t mA. Assume that the initial capacitor voltage is zero g

1.19. A gas is confined in a 0.47 m diameter cylinder by a piston, on which rests a weight. The mass of the piston and weight together is 150 kg. The local acceleration of gravity is 9.813 m·s−2, and atmospheric pressure is 101.57 kPa. (a) What is the force in newtons exerted on the gas by the atmosphere, the piston, and the weight, assuming no friction between the piston and cylinder? (b) What is the pressure of the gas in kPa? (c) If the gas in the cylinder is heated, it expands, pushing the piston and weight upward. If the piston and weight are raised 0.83 m, what is the work done by the gas in kJ? What is the change in potential energy of the piston and weight?\

Answers

In this exercise we have to use the knowledge of force to calculate the required energies, so we have to:

a) 19094 N

b) 110.055 kPa

c) 1222 J

What is the concept of force?

In the field of physics, force is a physical action that causes deformation or that changes the state of rest or movement of a given object.

a) Knowing that the force formula is defined by:

$F = P + p * A\nF = m * g + p *\pi /4 * d^2\nF = 150 * 9.813 + 101570 * \pi /4 * 0.47^2 = 19094 N$

b) Knowing that the force exerted by an area is equal to the pressure in that area, we have:

$p_1 = F / A\np_1 = F / (\pi /4 * d^2)\np_1 = 19094 / (\pi /4 * 0.47^2) = 110055 Pa = 110.055 kPa$

c)So calculating the potential energy we have:

$\Delta E_p = m * g * \Delta h\n\Delta E_p = 150 * 9.813 * 0.83 = 1222 J$

See more about force at brainly.com/question/26115859

Answer:

a) 19094 N

b) 110.055 kPa

c) 1222 J

Explanation:

The force on the gas is the weight plus the atmospheric pressure multiplied by the piston area

F = P + p * A

F = m * g + p * π/4 * d^2

F = 150 * 9.813 + 101570 * π/4 * 0.47^2 = 19094 N

The pressure is the force divided by the area of the piston

p1 = F / A

p1 = F / (π/4 * d^2)

p1 = 19094 / (π/4 * 0.47^2) = 110055 Pa = 110.055 kPa

variation of gravitational potential energy is defined as

ΔEp = m * g * Δh

ΔEp = 150 * 9.813 * 0.83 = 1222 J

For some transformation having kinetics that obey the Avrami equation (Equation 10.17), the parameter n is known to have a value of 2.1. If, after 146 s, the reaction is 50% complete, how long (total time) will it take the transformation to go to 86% completion?

Answers

Answer:

t = 25.10 sec

Explanation:

we know that Avrami equation

$Y = 1 - e^(-kt^n)$

here Y is percentage of completion of reaction = 50%

t is duration of reaction = 146 sec

so,

$0.50 = 1 - e^(-k^146^2.1)$

$0.50 = e^(-k306.6)$

taking natural log on both side

ln(0.5) = -k(306.6)

$k = 2.26* 10^(-3)$

for 86 % completion

$0.86 = 1 - e^{-2.26* 10^(-3) * t^(2.1)}$

$e^{-2.26* 10^(-3) * t^(2.1)} = 0.14$

$-2.26* 10^(-3) * t^(2.1) = ln(0.14)$

$t^(2.1) = 869.96$

t = 25.10 sec

With the aid of a labbled diagram describe the operation of a core type single phase transformer

Answers

Answer:

A simple single-phase transformer has each winding being wound cylindrically on a soft iron limb separately to provide a necessary magnetic circuit, which is commonly referred to as “transformer core”. It offers a path for the flow of the magnetic field to induce voltage between two windings.

In this type of projection, the angles between the three axes are different:- A) Isometric B) Axonometric C) Trimetric D) Dimetnic

Answers

Answer:

The correct answer is C) Trimetric

Explanation:

The most suitable answer is a trimetric projection because, in this type of projection, we see that the projection of the three angles between the axes are not equal. Therefore, to generate a trimetric projection of an object, it is necessary to have three separate scales.

_________ items are similar to the free issue items, but their access is limited. (CLO5) a)-Bin stock items free issue b)-Bin stock controlled issue c)-Critical or insurance spares d)-Rebuildable spares e)-consumables

Answers

Answer:

a)-Bin stock items free issue

Explanation:

Bin stock items free issue items are similar to the free issue items, but their access is limited.

Bin stock items free issue items are similar to the free issue items, but their access is limited.

Musk is working on developing reusable rockets in order to further us as a space-faring civilization. Given his life dedication to energy production, conservation, and efficiency, can you think of any other reasons that Musk may want to expand our ability to exist on other planets and in space?

Answers

Answer:

exploration

Explanation:

Other than the scientific reasons listed in the question, one of the main reasons why people all over the world are pursuing this endeavor is exploration. As human beings, we love to imagine new worlds and life-forms that we have never seen before. This fuels our need for exploration. Scientists throughout generations have dedicated their entire lives to learning and creating newer and better technology in order for humans to take that next step in exploring and learning the secrets of the universe.

Other Questions

can anyone help me with this please.i have the current and pf for branch 1 and 2 but cant figure out the total current, pf and angle. thanks

Which outcome most accurately portrays the future for the timber company in the following scenario?A timber company that cuts and sells its own wood has been in high demand for the past three years. The company has gone through many acres of forest in its area, but it is sure to plant tree seeds after it bulldozes a section.The timber company will lose business soon because not many people will need to build houses and buildings anymore.The timber company will run out of trees quickly because the seedlings will not have enough time to become full-grown timber.The timber company will go out of business due to the rising number of buildings using cement and concrete rather than timber.The timber company will continue to grow because of its good business practices, and it will become the number one timber company in the country.

What is 29.95 inHg in kPa?

The sports car has a weight of 4500-lb and a center of gravity at G. If it starts from rest it causes the rear wheels to slip as it accelerates. Determine how long it takes for it to reach a speed of 10 ft/s. Also, what are the normal reactions at each of the four wheels on the road? The coefficients of static and kinetic friction at the road are us=0.5 and uk=0.3, respectively. Neglect the mass of the wheels.