A bullet fired from a gun falls at a distance half of its maximum range. The angle of projection of the…

A bullet fired from a gun falls at a distance half of its maximum range. The angle of projection of the bullet is
  1. \(45^{\circ}\)
  2. \(60^{\circ}\)
  3. \(30^{\circ}\)
  4. \(15^{\circ}\)

Solution

As, we know that for a projectile motion, maximum range, \(R_{\max }=\frac{u^2}{g} \text { and } h_{\max }=\frac{R_{\max }}{4}\) Given, \(\quad R=\frac{R_{\max }}{2}\) \(\Rightarrow \quad \frac{R_{\max }}{2}=\frac{u^2}{2 g}=R\) ...(i) where, \(R=\frac{u^2 \sin 2 \theta}{g}\) Hence, \(\frac{u^2 \sin 2 \theta}{g}=\frac{u^2}{2 g}\) [From Eq. (i)] \(\Rightarrow \quad \sin 2 \theta=\frac{1}{2}\) \(\Rightarrow 2 \theta=30^{\circ} \Rightarrow \theta=15^{\circ}\) Hence, the correct option is (d).

Asked in: AP EAMCET 2019 (23 Apr Shift 1)

Practice more Motion In Two Dimensions questions on Aicharya