The radioactive substance strontium-90 has a half-life of 28 years. In other words, it takes 28 years for half of a given quantity of strontium-90 to decay to a non-radioactive substance. The amount of radioactive strontium-90 still present after t years is modeled by the expression 80 * 2^(-t/28) grams. Evaluate the expression for t = 0, t = 28 and t = 56. What does each value of the expression represent?

Question

anonymous · Answer

When t is 0, you get 80 grams, so that's the amount of strontium-90 you start with

When t = 28 is already answered in the question and so you should be able to work out what t = 56 represents as well......

anonymous · Answer

Im having trouble with the last part What does each value of the expression represent?

@estudier

anonymous · Answer

I already answered you above...?

anonymous · Answer

First, calculate the values when t = 0, 28 and 56

anonymous · Answer

t= 0 = 80 t = 28 = 40 t= 56 = 20 right?

anonymous · Answer

@estudier

anonymous · Answer

Right, now think.......You got 80 , 40 and 20 grams

Hint - Definition of half liife