Newton's law of cooling gives the temperature T(t) of an object at time tin terms of T0, its temperature at t = 0, and Ts, the temperature of the surroundings. 33
T(t) = T3 + (T0 - T3)e-kt
A police officer arrives at a crime scene in a hotel room at 9:18PM, where he finds a dead body. He immediately measures the body's temperature and find it to be 79.5° F. Exactly one hour later he measures the temperature again, and find it to be 78.0° F. Determine the time of death, assuming that victim body temperature was normal ( 98.6° F) prior to death, and that the room temperature was constant at 69° F.