A shot is fired from a point at a distance of \(200 \mathrm{~m}\), from the foot of a tower \(100…
- \(30^{\circ}\)
- \(60^{\circ}\)
- \(70^{\circ}\)
- \(45^{\circ}\)
Solution

Here, range, \(R=200+200=400 \mathrm{~m}\) Maximum height, \(H=100 \mathrm{~m}\) If \(\theta\) be the direction of shot with respect to horizontal, then \(\begin{aligned} & R=\frac{u^2 \sin 2 \theta}{g} \text { and } H=\frac{u^2 \sin ^2 \theta}{2 g} \\ & \therefore \quad \frac{R}{H}=\frac{\frac{u^2 \sin 2 \theta}{g}}{\frac{u^2 \sin ^2 \theta}{2 g}} \\ & \Rightarrow \quad \frac{400}{100}=\frac{2 \sin 2 \theta}{\sin ^2 \theta} \\ & \Rightarrow \quad 4=\frac{2 \times 2 \sin \theta \cos \theta}{\sin ^2 \theta} \quad [\because \sin 2 \theta=2 \sin \theta \cos \theta] \\ & \Rightarrow \quad 1=\tan \theta \\ & \Rightarrow \quad \tan 45^{\circ}=\tan \theta \\ & \Rightarrow \quad 45^{\circ}=\theta \\ & \Rightarrow \quad \theta=45^{\circ} \\ \end{aligned}\)
Asked in: AP EAMCET 2020 (21 Sep Shift 1)
Practice more Motion In Two Dimensions questions on Aicharya