# pre calc

posted by andi

A 50 gram sample of radioactive strontium will decay to 32 grams in 18 years.
a. Find an equation that will model how much of our sample M will remain after t years.

1. Henry

(50-32)grams/18yrs = 1 Gram/yr.

Mr = M-1*T = M-T = 50 - 18 = 32 grams. = Mass remaining.

2. Henry

Correction: The decay rate is exponential.

50/e^x = 32, e^x = 50/32 = 1.5625, X = 0.446 = kt, K = 0.446/t = 0.446/18 = 0.0248.

Mr = M/e^kt = M/e^(0.0248t) = Mass remaining.

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