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2.Motion in Straight Line
hard
A body is projected up with a speed $'u'$ and the time taken by it is $T$ to reach the maximum height $H$. Pick out the correct statement
A
It reaches $H/2$ in $T/2$ sec
B
It acquires velocity $u/2$ in $T/2\sec $
C
Its velocity is $u/2$ at $H/2$
D
Same velocity at $2T$
Solution
(b) At maximum height velocity $v = 0$
We know that $v = u + at$, hence
$0 = u – gT \Rightarrow u = gT$
When $v = \frac{u}{2}$, then
$\frac{u}{2} = u – gt \Rightarrow gt = \frac{u}{2} \Rightarrow gt = \frac{{gT}}{2} \Rightarrow t = \frac{T}{2}$
Hence at $t = \frac{T}{2}$, it acquires velocity $\frac{u}{2}$
Standard 11
Physics
