Q56 / 75 · JEE Main 2025 (29 Jan Shift 1) · Physics

Two projectiles are fired with same initial speed from same point on ground at angles of \(\left(45^{\circ}-\alpha\right)\) and \(\left(45^{\circ}+\alpha\right)\), respectively, with the horizontal direction. The ratio of their maximum heights attained is :

  • A
    \(\frac{1-\tan \alpha}{1+\tan \alpha}\)
  • Correct answer
    B
    \(\frac{1-\sin 2 \alpha}{1+\sin 2 \alpha}\)
  • C
    \(\frac{1+\sin 2 \alpha}{1-\sin 2 \alpha}\)
  • D
    \(\frac{1+\sin \alpha}{1-\sin \alpha}\)

Solution

$\begin{aligned} & \mathrm{H}_{\mathrm{Max}}=\frac{(\mathrm{u} \sin \theta)^2}{2 \mathrm{~g}} \\ & \frac{\left(\mathrm{H}_{\max }\right)_1}{\left(\mathrm{H}_{\max }\right)_2}=\frac{\mathrm{u}^2 \sin ^2(45-\alpha)}{\mathrm{u}^2 \sin ^2(45+\alpha)} \\ & =\frac{\left(\frac{1}{\sqrt{2}} \cos \alpha-\frac{1}{\sqrt{2}} \sin \alpha\right)^2}{\left(\frac{1}{\sqrt{2}} \cos \alpha+\frac{1}{\sqrt{2}} \sin \alpha\right)^2} \\ & =\frac{1-\sin 2 \alpha}{1+\sin 2 \alpha}\end{aligned}$

Hence, the correct answer is option: 'B'.

Relevant Questions