Q. 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 $T/2sec$
C) Its velocity is $u/2$ at $H/2$
D) Same velocity at $2T$
Explanation
(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 $\frac{u}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.