Iodine-131 has a half life of 8 days, so half of it is gone every 8 days.
10 grams of iodine-131 is left for 24 days.
At 8 days: 10/2=5 grams left
At 16 days: 5/2=2.5 grams left
At 24 days: 2.5/2=1.25 grams left.
**
Your mistake is that you stopped at 16 days.
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Use the following kinematic equation to solve for the final velocity:
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In this instance, the runner started from rest, so the initial velocity is 0 m/s. We can rewrite the equation as:
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Plug in the given acceleration and time:
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