Growth and decay (1 Viewer)

[ghostman_on_3rd]

Hi how do you do this question?

An oven has been heated to a constant temperature of 250*c. An object with a temperature of 10*c is placed in the oven and after 15minutes its temperature is measured as 70*c

What will be the temperature of the object after 30minutes?

thanks in advance

 

[oly1991]

T = C + Ae*-kt
10 = 250 + Ae*0
A = -240
when t = 15, T = 70
70 = 250 + -240*-15k
ln0.75 = -15klne
k = ln0.75/-15 (lne = 1)
= 0.019178804......
when t=30
T = 250 - 240e*-30k
=114.99...