If two stones are projected at angle ' $ heta$ ' and $(90- heta)$ respectively with horizontal with a speed of $20 \mathrm{~ms}^{-1}$. If second stone rises 10 m higher than the first stone, then the angle of projection ' $ heta$ ' is (acceleration clue to gravity $=10 \mathrm{~ms}^{-2}$ )

Question

If two stones are projected at angle ' $	heta$ ' and $(90-	heta)$ respectively with horizontal with a speed of $20 \mathrm{~ms}^{-1}$. If second stone rises 10 m higher than the first stone, then the angle of projection ' $	heta$ ' is (acceleration clue to gravity $=10 \mathrm{~ms}^{-2}$ )

Aicharya · Accepted Answer

$\begin{aligned} & \quad \mathrm{u}=20 \mathrm{~ms}^{-1} \ & \mathrm{H}_2=\mathrm{H}_1+10 \Rightarrow \frac{\mathrm{u}_2^2 \sin ^2\left(90^{\circ}-	hetaight)}{2 \mathrm{~g}}=\frac{\mathrm{u}_1^2 \sin ^2 	heta}{2 \mathrm{~g}}+10 \ & \Rightarrow \frac{(20)^2 \cdot \cos ^2 	heta}{20}=\frac{(20)^2 \sin ^2 	heta}{20}+10 \ & \Rightarrow \cos 2 	heta=\frac{1}{2}=\cos 60^{\circ} \ & 	herefore \quad \ & 	heta=30^{\circ}\end{aligned}$

If two stones are projected at angle ' $\theta$ ' and $(90-\theta)$ respectively with horizontal with a…

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