$\bf \textit{volume of a cylinder}\\\\
V=\pi r^2 h\qquad 
\begin{cases}
r=radius=\frac{diameter}{2}\\
h=height\\
----------\\
diameter=1.8\\
r=\frac{1.8}{2}=0.9\\
h=5
\end{cases}\implies V=\pi \cdot 0.9^2\cdot 5\\\\
-------------------------------\\\\
\textit{is draining at }\boxed{2.1}\ \frac{ft^3}{min}\textit{ , it has a total of }\boxed{\pi \cdot 0.9^2\cdot 5} \ ft^3
\\\\\\
\textit{it'll take }\cfrac{\pi \cdot 0.9^2\cdot 5}{2.1}\ minutes$

3 0

3 years ago

Using Newton's Law of Cooling. You are a medical examiner called to an abandoned house in which a dead body has been discovered.

Artyom0805 [142]

A) The differential equation comes from the fact that the rate of temperature change is proportional to the difference in temperatures.
$\frac{dT}{dt} = \alpha(T -52)$

B) Find general solution by separating variables and integrating $\int\frac{dT}{T-52} = \alpha \int dt \\ ln (T-52) = \alpha t + C \\ T = C e^{\alpha t} +52$ :

C) Initial condition is t=0, T = 87
$87 = C +52 \\ C = 35$

D) Total time elapsed is 10 minutes, new temperature is 84
$84 = 35 e^{10\alpha} +52$
solve for alpha
$e^{10\alpha} =\frac{32}{35} \\ \alpha = \frac{ln(32/35)}{10} \\ \alpha = -.00896$

E) Temperature function is:
$T = 35 e^{-.00896 t} +52$
solving for t
$t = \frac{ln (\frac{T-52}{35})}{-.00896}$
Plug in T = 98.6
$t = -31.95$

This is approximately 32 minutes before he arrived or about 1:20 AM

3 0

3 years ago

Answer to the question

nadezda [96]

Answer:

B. DC = 29 and DE = 44.5

Step-by-step explanation:

DC = AB
29 = 29

I honestly don't know how to get DE but because DC has to be 29, the second option is the only right answer

6 0

3 years ago