Two projectiles are fired with same initial speed from same point on ground at angles of…

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 :
  1. \(\frac{1-\tan \alpha}{1+\tan \alpha}\)
  2. \(\frac{1-\sin 2 \alpha}{1+\sin 2 \alpha}\)
  3. \(\frac{1+\sin 2 \alpha}{1-\sin 2 \alpha}\)
  4. \(\frac{1+\sin \alpha}{1-\sin \alpha}\)

Solution

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

Asked in: JEE Main 2025 (29 Jan Shift 1)

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