Answer:
a. ![\frac{dT}{dt}=k(T-Tm); T(0)=190](https://tex.z-dn.net/?f=%5Cfrac%7BdT%7D%7Bdt%7D%3Dk%28T-Tm%29%3B%20T%280%29%3D190)
b. ![C_{0}=122](https://tex.z-dn.net/?f=C_%7B0%7D%3D122)
c. ![k=-0.00259](https://tex.z-dn.net/?f=k%3D-0.00259)
d.
minutos
Step-by-step explanation:
a. Newton's law of cooling states that the speed with which a body is cooled is proportional to the difference between its temperature and that of the medium in which it is found. Then, the initial value problem is given by:
![Tm=68](https://tex.z-dn.net/?f=Tm%3D68)
![\frac{dT}{dt}=k(T-Tm); T(0)=190](https://tex.z-dn.net/?f=%5Cfrac%7BdT%7D%7Bdt%7D%3Dk%28T-Tm%29%3B%20T%280%29%3D190)
b. The differential equation obtained is a differential equation of separable variables:
![\frac{dT}{T-Tm}=kdt\\\\\int {\frac{dT}{T-Tm}}=\int{kdt}\\\\Ln|T-Tm|=kt+C\\\\T(t)=C_{0}e^{kt}+Tm=C_{0}e^{kt}+68\\\\T(0)=C_{0}e^{k(0)}+68=190\\\\C_{0}=122](https://tex.z-dn.net/?f=%5Cfrac%7BdT%7D%7BT-Tm%7D%3Dkdt%5C%5C%5C%5C%5Cint%20%7B%5Cfrac%7BdT%7D%7BT-Tm%7D%7D%3D%5Cint%7Bkdt%7D%5C%5C%5C%5CLn%7CT-Tm%7C%3Dkt%2BC%5C%5C%5C%5CT%28t%29%3DC_%7B0%7De%5E%7Bkt%7D%2BTm%3DC_%7B0%7De%5E%7Bkt%7D%2B68%5C%5C%5C%5CT%280%29%3DC_%7B0%7De%5E%7Bk%280%29%7D%2B68%3D190%5C%5C%5C%5CC_%7B0%7D%3D122)
c. After 33 minutes of serving the coffee has cooled to 180°:
![T(33)=122e^{33k}+68=180\\\\e^{33k}=\frac{112}{122}\\\\33k=Ln(\frac{112}{122})\\\\k=-0.00259](https://tex.z-dn.net/?f=T%2833%29%3D122e%5E%7B33k%7D%2B68%3D180%5C%5C%5C%5Ce%5E%7B33k%7D%3D%5Cfrac%7B112%7D%7B122%7D%5C%5C%5C%5C33k%3DLn%28%5Cfrac%7B112%7D%7B122%7D%29%5C%5C%5C%5Ck%3D-0.00259)
d.
![150=122e^{-0.00259t}+68\\\\Ln(\frac{150-68}{122})=-0.00259t\\\\t=153.39838\\\\](https://tex.z-dn.net/?f=150%3D122e%5E%7B-0.00259t%7D%2B68%5C%5C%5C%5CLn%28%5Cfrac%7B150-68%7D%7B122%7D%29%3D-0.00259t%5C%5C%5C%5Ct%3D153.39838%5C%5C%5C%5C)
Answer:
24
Step-by-step explanation:
Answer:
12 3/8 feet
Step-by-step explanation:
Because 4 1/2 times 2 3/4 equals 99/8, then 99 divided by 8 equals 12 3/8.
When doing that it will be B
The answer is anyghiun less than 1 so
0.1 kg is correct
but, 1kg=1000g so
999g is also correct