Motion In A Straight Line Ques 2
2. A ball is thrown vertically upward. It has a speed of $10 $ $\mathrm{m} / \mathrm{sec}$ when it has reached one half of its maximum height. How high does the ball rise?
[2001, 2005]
Take $g=10 $ $\mathrm{m} / \mathrm{s}^2$.
(a) $10 $ $\mathrm{m}$
(b) $5 $ $\mathrm{m}$
(c) $15$ $ \mathrm{m}$
(d) $20$ $ \mathrm{m}$
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Answer:
Correct Answer: 2.(a)
Solution: (a) For part $AB$
From $3^\text{rd}$ equation of motion
$v^2=u^2+2 \mathrm{gH}$
$ \begin{alignedat} & 0=u^2-2 \mathrm{g}(\mathrm{H} / 2)=u^2-\mathrm{gH} \\ & \mathrm{H}=\frac{u^2}{g}=\frac{10^2}{10}=10 \mathrm{m} \end{aligned} $
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