Vector question,university physics zemanski

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

Bond [772]

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.

3 0

3 years ago

An object in a fluid experiences a buoyant force from the fluid. If the object is completely immersed, on which does the magnitu

loris [4]

Answer:

Weight of the fluid that the object displaces.

Explanation:

When the fluid is completely immersed in a fluid, it experiences pressure from all the direction. While the object is immersed in the fluid a force acts on it in the opposite direction, i.e., upwards. This force is termed as buoyant force.

Also, as per the Archimedes' Principle, the force experience by the object is the same as the weight of the fluid that gets displaced by the object.

Thus on complete immersion of the object in the fluid, it experiences the force same as the weight of the fluid that gets displaced

4 0

3 years ago

A 55 kilogram person jumps off a cliff and hits the water 5.8 seconds later, how high is the cliff above the water?

ElenaW [278]

R=ut+gt^2/2
r- displacement (height to find)
u - initial speed (zero)
t - time taken

r=0*5.8 + 10*5.8^2 /2 = 168.2 meters

8 0

3 years ago

How does the density of most metals compare to most non metals?

Neko [114]

Harder. Not compressible(unless using an extremely strong force). Non-metal have more of a chance of breaking than metals.

8 0

3 years ago

The blood pressure in the human body is greater at the feet than at the brain

GarryVolchara [31]

Blood pressure is greater in feet because of gravity

5 0

3 years ago

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