Q86 / 90 · JEE Main 2024 (05 Apr Shift 2) · Physics
The maximum height reached by a projectile is $64 \mathrm{~m}$. If the initial velocity is halved, the new maximum height of the projectile is _____ $\mathrm{m}$.
Correct answer: 16
Solution
$\begin{aligned} & \mathrm{H}_{\max }=\frac{\mathrm{u}^2 \sin ^2 \theta}{2 \mathrm{~g}} \\ & \frac{\mathrm{H}_{1 \text { max }}}{\mathrm{H}_{2 \max }}=\frac{\mathrm{u}_1^2}{\mathrm{u}_2^2} \\ & \frac{64}{\mathrm{H}_{2 \max }}=\frac{\mathrm{u}^2}{(\mathrm{u} / 2)^2} \\ & \mathrm{H}_{2 \max }=16 \mathrm{~m}\end{aligned}$
Hence, the correct answer is 16.