Engineering Board Exam Reviewer · Applications: Cooling, Heating, and Mixture Problems · easy

A body at 100° C is placed in a room kept at 20° C. It cools to 60° C in 10 minutes. What is its temperature after 20 minutes?

  1. 40° C
  2. 20° C
  3. 36° C
  4. 30° C

Answer

A. 40° C

Solution

T-20=80ekt. At t=10: 40=80e10k e10k= 12. At t=20: T-20=80· 14=20 T=40° C.

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