Physics, 28.11.2019 04:31 janeou17xn

Suppose you stand with one foot on ceramic flooring and one foot on a wool carpet, making contact over an area of 80.0 cm2 with each foot. both the ceramic and the carpet are 2.00 cm thick and are 10.0∘c on their bottom sides. at what rate must heat transfer occur from each foot to keep the top of the ceramic and carpet at 33.0∘c?

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Answer from: dondre54

To solve this problem it is necessary to apply the concepts related to the rate of heat transfer in the materials.

By definition the rate of heat conduction transferred is understood as

$\frac{Q}{t} = \frac{kA(T_2-T_1)}{d}$

Where,

$\frac{Q}{t} =$ Rate of heat transfer

k = Thermal conductivity

A = Surface area

d = Thickness

$T_{1,2} =$ Temperature at different states.

Our values are given as,

$k_w = 0.04J/s.m.\°C\\k_c = 0.84J/s.m.\°C\\A = 80*10^{-4}m^2\\d= 2cm\\T_2 = 33\°CT_1 = 10\°C$

Substituting for the wood carpet we have,

$\frac{Q}{t} = \frac{kA(T_2-T_1)}{d}\\\frac{Q}{t} = \frac{(0.04)(80*10^{-4})(33-10)}{2*10^{-2}}\\\frac{Q}{t} = 0.369W$

Substituting for the ceramic we have,

$\frac{Q}{t} = \frac{kA(T_2-T_1)}{d}\\\frac{Q}{t} = \frac{(0.84)(80*10^{-4})(33-10)}{2*10^{-2}}\\\frac{Q}{t} = 7.728W$

Therefore the rate of heat transfer for the wood carpet is 0.37W while the rate of heat transfer for the ceramic is 7.7W

Answer from: Quest

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this

Answer from: Quest

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