Answer:
16.2 days
Explanation:
Find the number of halflives:
1/2 * 1/2 = 1/4 so <u>two</u> halflives have passed
2 * 8.1 days = 16.2 days
The answer is option C .Because as the direction of the boy changes ;velocity changes .
Up ward direction...
Positive direction
Because it is not a good conductor of heat. so the answer is D.
