Question

A glass baking dish (Ԑ= 0.9, c =840J/(kgoC)) has a mass of 1.94 kg and comes out of the oven at about 450oF (232oC). It is 39 cm long, 34 cm wide and the sides are 6 cm high (you can make the approximation that both sides of the walls are 6 cm high). [6]

a. How much heat must be lost before the dish returns to 36o C, cool enough to touch?

b.How long will it take to radiate away this heat in a room that is 21oC so the glass can be touched? Assume the dish radiates heat from both sides of all five of its surfaces.

c. If the same quantity of glass were in a cube, each side would be 9.55 cm long. How long would it take to radiate the heat away if the glass were in a cube?

Answer 1