A plot of coffee has been allowed to cool to 17?C. If the electrical coffee maker is turned back on, the hot plate on which the pot rests is brought up to 70?C immediately and held at that temperature by a thermostat. Consider the pot to be a vertical cylinder 130 mm in diameter and the depth of coffee in the pot to be 100 mm. Neglect heat losses from the sides and top of the pot. How long will it take before the coffee is drinkable (50?C)? How much did it cost to heat the coffee if electricity costs $0.05 per kilowatt-hour?GIVENCoffee pot, idealized as a vertical cylinder, on a hot plateInitial temperature of the pot and coffee (Ts,i) = 17?CHot plate temperature (Thp) = 70?C (constant)Pot diameter (D) = 130 mm = 0.13 mDepth of coffee (δ) = 100 mm = 0.1 mASSUMPTIONSHeat losses from the sides and the top are negligibleAll energy from the hot plate goes into the coffeeInternal resistance of the coffee is negligibleThermal resistance of the bottom of the pot is negligibleCoffee has the thermal properties of waterVariation of the thermal properties of the coffee with temperature can beneglected

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Coffee Level TA= 17°C L=0.1 m Hot Pad, Thp = 70°C D 0.13 m