Q225 / 225 · JEE Main 2004 · Physics
If $t_1$ and $t_2$ are the times of flight of two particles having the same initial velocity $u$ and range $\mathrm{R}$ on the horizontal, then $\mathrm{t}_1^2+\mathrm{t}_2^2$ is equal to
- A$\frac{u^2}{g}$
- Correct answerB$\frac{4 u^2}{g^2}$
- C$\frac{u^2}{2 g}$
- D1
Solution
$\mathrm{t}_1=\frac{2 \mathrm{u} \sin \alpha}{\mathrm{g}}, \mathrm{t}_2=\frac{2 \mathrm{u} \sin \beta}{\mathrm{g}}$ where $\alpha+\beta=90^{\circ}$
$\therefore \mathrm{t}_1^2+\mathrm{t}_2^2=\frac{4 \mathrm{u}^2}{\mathrm{~g}^2}$
Hence, the correct answer is option: 'B'.