Answer:
If there is a shaft with headgear, then mining can take place until that depth of the shaft. If it is accessed horizontal Adits, it can mine until the lowest Adit from upwards. If it is accessed decline, the development and mining can continue so long as economic exploitation is possible.
Explanation:
What are the disadvantages of mining headgear? They totally cut off your vision of anything above your head. They are hot, most of the time
Answer:
The rate of energy absorbed per unit time is 3500W.
Explanation:
From the question, we were given the following parameters;
Plane, opaque, gray, diffuse surface
â = 0.7
Surface area, A = 0.5m²
Incoming radiant energy, G = 10000w/m²
T = 500°C
Rate of energy absorbed is âAG;
âAG = 0.7 × 0.5 × 10000
âAG = 3500W.
The energy absorbed is measured in watts and denoted by the symbol W.
Answer and Explanation:
In thermodynamics, the overall heat transfer coefficient also referred as film effectiveness is a constant of proportionality between force drive for the heat flow and the heat flux.
It gives the measure of the heat transfer as a result of convection or conduction. The coefficient of overall heat transfer depends on surface area, resistance of the material, temperature difference, thickness, etc.
It is given by:
Q = UA
where
U = overall heat transfer coefficient
Its SI units is 
.
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