A 2 kg block of iron is to be dropped from the roof of a tall building. The initial temperature of the iron is 25oC, and the height of the building is 150 m.
(a) Assuming that the block is insulated and ignoring the effects of the atmosphere, determine the final temperature of the iron when it comes to rest on the ground.
(b) Develop a computer model for this problem, and plot the final temperature of the iron that would be expected for building heights ranging from 10 m to 500 m.
Given: Fe; m = 2 kg; T1 = 25oC; z1 = 150 m; z2 = 0 m
Assume: Q = W = ?KE = 0; The iron is an incompressible substance with constant specific heats: c = 0.447 kJ/kg-K = 447 J/kg-K
What will be an ideal response?
Solution: (a) The First Law for this closed system reduces to
(b) Using these equations, the temperatures expected for the range of building heights are
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