The temperature of a cup of water drops by 44^{o}F when it is placed in a refrigerator for 45 minutes. How much did the temperature of the water change in K, ^{o}R and in ^{o}C. 











Read: 
The key to this
problem is that we are considering a CHANGE in temperature and NOT a temperature of 27^{o}C. 










Given: 
DT 
44 
^{o}F 
















Find: 
DT 
??? 
K 



DT 
??? 
^{o}C 

DT 
??? 
^{o}R 









^{} 






Assumptions: 
None. 

















Equations
/ Data / Solve: 


















Start with
Rankine. The temperature increments
for the Fahrenheit and Rankine scales are the same. Therefore : 

















DT 
44 
^{o}R 











Next, let's work on
getting DT in the Kelvin
scale. 






This is
straightforward because a temperature change of 1 K is equal to a temperature
change of 1.8 ^{o}R. 

















Eqn 1 

















DT 
24.444 
K 











Finally, the
temperature increments for the Celsius and Kelvin scales are the same. 











Therefore : 





DT 
24.444 
^{o}C 










Answers: 
DT 
24.4 
K 







DT 
44 
^{o}R 







DT 
24.4 
^{o}C 















