The half life of strontium 90 is 28 years. Suppose we have a 76 mg sample.
a)find a function that models the mass m(t) remaining after t years.
b)how much of the sample will remain after 70 years?
a)find a function that models the mass m(t) remaining after t years.
b)how much of the sample will remain after 70 years?
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a)
A = 76 * (1/2)^(t / 28)
b)
A = 76 * (1/2)^(70 / 28)
A = 76 * (1/2)^(5/2)
A = 76 * (1/2) * (1/2) * (1/2) * sqrt(2)
A = 19 * sqrt(2) / 2
A = 9.5 * sqrt(2)
A = 13.435028842544402963616042879992
A = 76 * (1/2)^(t / 28)
b)
A = 76 * (1/2)^(70 / 28)
A = 76 * (1/2)^(5/2)
A = 76 * (1/2) * (1/2) * (1/2) * sqrt(2)
A = 19 * sqrt(2) / 2
A = 9.5 * sqrt(2)
A = 13.435028842544402963616042879992