Q109 / 180 · JIPMER 2019 · Physics
If three objects are thrown with velocity $\sqrt{\frac{2 g H}{3}}, \sqrt{2 \mathrm{gH}}, \sqrt{\frac{g H}{3}}$, then find the ratio of their maximum heights.
- Correct answerA$2: 6: 1$
- B$2: 5: 3$
- C$2: 4: 7$
- D$3: 7: 4$
Solution
Maximum height of projectile $\mathrm{H}_{\max }=\frac{\mathrm{u}^2}{2 \mathrm{~g}}$
$\begin{aligned}
& \therefore\left(\mathrm{H}_{\max }\right)_1:\left(\mathrm{H}_{\max }\right)_2:\left(\mathrm{H}_{\max }\right)_3 \\
&=\frac{\left(\sqrt{\frac{2 \mathrm{gH}}{3}}\right)^2}{2 \mathrm{~g}}: \frac{(\sqrt{2 \mathrm{gH}})^2}{2 \mathrm{~g}}: \frac{\sqrt{\frac{\mathrm{gH}}{3}}}{2 \mathrm{~g}}=\frac{2}{3}: 2: \frac{1}{3} \\
& \quad=2: 6: 1
\end{aligned}$
Hence, the correct answer is option: 'A'.