1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
OleMash [197]
2 years ago
15

Thermopane window is constructed, using two layers of glass 4.0 mm thick, separated by an air space of 5.0 mm.

Physics
1 answer:
Bond [772]2 years ago
3 0

To solve this problem it is necessary to apply the concepts related to rate of thermal conduction

\frac{Q}{t} = \frac{kA\Delta T}{d}

The letter Q represents the amount of heat transferred in a time t, k is the thermal conductivity constant for the material, A is the cross sectional area of the material transferring heat, \Delta T, T is the difference in temperature between one side of the material and the other, and d is the thickness of the material.

The change made between glass and air would be determined by:

(\frac{Q}{t})_{glass} = (\frac{Q}{t})_{air}

k_{glass}(\frac{A}{L})_{glass} \Delta T_{glass} = k_{air}(A/L)_{air} \Delta T_{air}

\Delta T_{air} = (\frac{k_{glass}}{k_{air}})(\frac{L_{air}}{L_{glass}}) \Delta T_{glass}

\Delta T_{air} = (\frac{0.84}{0.0234})(\frac{5}{4}) \Delta T_{glass}

\Delta T_{air} = 44.9 \Delta T_{glass}

There are two layers of Glass and one layer of Air so the total temperature would be given as,

\Delta T = \Delta T_{glass} +\Delta T_{air} +\Delta T_{glass}

\Delta T = 2\Delta T_{glass} +\Delta T_{air}

20\°C = 46.9\Delta T_{glass}

\Delta T_{glass} = 0.426\°C

Finally the rate of heat flow through this windows is given as,

\Delta {Q}{t} = k_{glass}\frac{A}{L_{glass}}\Delta T_{glass}

\Delta {Q}{t} = 0.84*24*10 -3*0.426

\Delta {Q}{t} = 179W

Therefore the correct answer is D. 180W.

You might be interested in
During the spin cycle of a washing machine, the clothes stick to the outer wall of the barrel as it spins at a rate as high as 1
Darya [45]

To answer the two questions, we need to know two important equations involving centripetal movement:

v = ωr (ω represents angular velocity <u>in radians</u>)

a = \frac{v^{2}}{r}

Let's apply the first equation to question a:

v = ωr

v = ((1800*2π) / 60) * 0.26

Wait. 2π? 0.26? 60? Let's break down why these numbers are written differently. In order to use the equation v = ωr, it is important that the units of ω is in radians. Since one revolution is equivalent to 2π radians, we can easily do the conversion from revolutions to radians by multiplying it by 2π. As for 0.26, note that the question asks for the units to be m/s. Since we need meters, we simply convert 26 cm, our radius, into meters. The revolutions is also given in revs/min, and we need to convert it into revs/sec so that we can get our final units correct. As a result, we divide the rate by 60 to convert minutes into seconds.

Back to the equation:

v = ((1800*2π)/60) * 0.26

v = (1800*2(3.14)/60) * 0.26

v = (11304/60) * 0.26

v = 188.4 * 0.26

v = 48.984

v = 49 (m/s)

Now that we know the linear velocity, we can find the centripetal acceleration:

a = \frac{v^{2}}{r}

a = \frac{49^{2}}{0.26}

a = 9234.6 (m/s^{2})

Wow! That's fast!

<u>We now have our answers for a and b:</u>

a. 49 (m/s)

b. 9.2 * 10^{3} (m/s^{2})

If you have any questions on how I got to these answers, just ask!

- breezyツ

5 0
2 years ago
A satellite is in orbit 36000km above the surface of the earth. Its angular velocity is 7.27*10^-5 rad/s. What is the velocity o
bagirrra123 [75]

Answer:

v = 3.08 km/s

Explanation:

Given that,

The angular velocity of the satellite = \omega=7.27\times 10^{-5} rad/s

A satellite is in orbit 36000km above the surface of the earth.

The radius of the earth is 6400 km

Let v is the velocity of the satellite. It can be calculated as :

v=r\omega\\\\v=(36000\times 10^3+6400\times 10^3)\times 7.27\times 10^{-5}\\\\v=3082.48\ m/s\\\\v=3.08\ km/s

So, the velocity of the satellite is 3.08 km/s.

6 0
2 years ago
A greyhound's velocity changes from 10 meters per second to 15 meters per second in 0.5 second. What is the greyhound's average
alexgriva [62]
I think it is 5 m/s  
4 0
3 years ago
Read 2 more answers
Why can friction make observing Newton's first law of motion difficult?
Kamila [148]
The law says things travel in a straight line at constant speed unless acted upon by a force.  But friction is a force but it can't be seen easily other than its effect, which is to bring the object to rest in seeming violation of the 1st law.
6 0
3 years ago
A student says that since the atomic theory is just a theory, it should not be considered useful. Which statement best argues ag
yarga [219]
Theories are usually backed up with a lot of evidence. If the evidence is well studied then it is useful information.
4 0
3 years ago
Other questions:
  • What mass of silver can be plated onto an object in 33.5 minutes at 8.70 a of current? ag (aq e- ? ag(s what mass of silver can
    14·2 answers
  • A uniform disk turns at 5.00 rev/s around a frictionless spindle. A non-rotating rod, of the same mass as the disk and length eq
    10·1 answer
  • An electron is released from rest in a weak electric field given by E,--2.50 x 10.10 N/C j. After the electron has traveled a ve
    7·1 answer
  • A car traveling at 37m/s starts to decelerate steadily. It comes to a complete stop in 15 seconds. What is it’s acceleration
    15·1 answer
  • A bullet that has been too badly mutilated to mark can be
    7·1 answer
  • An air bubble at the bottom of a lake 52.0 m deep has a volume of 1.50m^3. If the temperature at the bottom is 5.5 degree's Cels
    15·1 answer
  • How does a pendalum conserve energy
    15·1 answer
  • When a body is accelerated under water, some of the surrounding water is also accelerated. This makes the body appear to have a
    15·1 answer
  • HELP! how did michael jordan influence future basketball players to make prodcuts?
    5·2 answers
  • Two 1.50-V batteries-with their positive terminals in the same direction-are inserted in series into a flashlight. One battery h
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!