SOLUTION: After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1988​, the hay in that country was contaminated by a radioactive isot
Algebra ->
Customizable Word Problem Solvers
-> Misc
-> SOLUTION: After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1988​, the hay in that country was contaminated by a radioactive isot
Log On
Question 1088727: After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1988, the hay in that country was contaminated by a radioactive isotope (half-life 6 days). If it is safe to feed the hay to cows when 14% of the radioactive isotope remains, how long did the farmers need to wait to use this hay?
The farmers needed to wait approximately ____ days for it to be safe to feed the hay to the cows?
(Round to one decimal place as needed.) Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! After the release of radioactive material into the atmosphere from a nuclear power plant in a country in 1988, the hay in that country was contaminated by a radioactive isotope (half-life 6 days).
If it is safe to feed the hay to cows when 14% of the radioactive isotope remains, how long did the farmers need to wait to use this hay?
:
using the radioactive decay formula: A = Ao*2^(-t/h), where
A = remaining amt after t time
Ao = initial amt
t = time of decay
h = half-life of substance
:
let initial amt = 1
then
resulting amt = .14
:
1*2^(-t/6) = .14
use nat logs
ln(2^(-t/6)) = ln(.14)
the log equiv of exponents *ln(2) = ln(.14 =
using your calc we have = -2.8365
multiply both sides by -6
t = 17.02 days before using the hay
