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A hot cup of black coffee (85°C) is placed on a tabletop (22°C) where it remains....

A hot cup of black coffee (85°C) is placed on a tabletop (22°C) where it remains. The surrounding room is at a temperature of 22°C. The cup is cylindrical in shape with a height of 15.0 cm and an outside diameter of 8.00 cm. The cup is made of ceramic with a thermal conductivity of 0.84 W/m°C. The outside of the cup has a temperature of 60°C and the cup is 6.0 mm in thickness. A slight breeze is blowing in the room.

A) What is the rate of heat loss due to convection from the top of the coffee? Use a convection coefficient of 10W/m2°C for the coffee's surface. ? W Give your answer as positive since we are calculating the magnitude of the rate of loss.

B) What is the total rate of heat loss for the coffee? ? W. Give your answer as positive since we are calculating the magnitude of the rate of loss.

C) If the rate of cooling is assumed to be constant, how long will the coffee take to reach a temperature of 25°C? t=? minutes

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genius_generous answered 2 years ago
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