The correct answer is option B. The maximum height that can be reached by the stone is determined as 11.5 m.
The maximum height attained by the stone when it is a 2/3 of its total height is calculated as follows;
v² = u² - 2gh
where;
0 = u² - 2gh
2gh = u²
h = u²/2g
h = (15²)/(2 x 9.8)
h = 11.48 m
h = 11.5 m
Thus, the maximum height that can be reached by the stone is determined as 11.5 m
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