Answer:
ΔT = ΔT0 e^-K T
As I understand Newton's Law of Cooling
ΔT at any time is the difference between the temperature and the surroundings
Originally ΔT0 = 95 - 22 difference between 95 and room temperature
65 - 22 = 33 = 73 e^-KT where t is time to cool to 65 deg
ln (33/73) = -KT K = .794 / 5 = .159 where 5 is time to cool to 65 deg
40 - 22 = 73 e^-.159 T where t is time to cool to 40 deg
18 = 73 e^-.159 T
ln (18 / 73) = -.159 T
T = 8.8 min
It would take 8.8 min for the object to cool to 40 deg C
Suppose the object cooled from 95 to 90 deg, then
ln 68 / 73 = -.159 T and T = .45 min
Quotients can sometimes be irrational so it is necessary to estimate them, products on the other hand are only rational, provided they aren't multiplied by an irrational, so it is not necessary to estimate
Surface area o fthe ball = 4 * 3.14 * radius^2
if diameter = 1.680 then radius = 1/2 * 1.680 = 0.84
so surface area = 4 * 3.14 * 0.84^2 = 8.862
we know that
The simple interest formula is equal to
where
P is the Principal amount of money to be invested
I is the amount of money in interest
r is the rate of interest
t is Number of Time Periods
in this problem we have
substitute in the formula above and solve for P
![P=14.65/[(0.025)(2)]](https://tex.z-dn.net/?f=P%3D14.65%2F%5B%280.025%29%282%29%5D)
therefore
<u>the answer is</u>
