Q. A projectile is fired at an angle of $45{^\circ}$ with the horizontal. Elevation angle of the projectile at its highest point as seen from the point of projection, is:

A) $\tan^{- 1}\left( \frac{\sqrt{3}}{2} \right)$
B) $45{^\circ}$
C) $60{^\circ}$
D) $\tan^{- 1}\frac{1}{2}$
Explanation

(d) $H = \frac{u^{2}\sin^{2}{45{^\circ}}}{2g} = \frac{u^{2}}{4g}$ …(i)
$R = \frac{u^{2}\sin{90{^\circ}}}{g} = \frac{u^{2}}{g}$
[image:4_image163.emf]
$\therefore\frac{R}{2} = \frac{u^{2}}{2g}$ …(ii)
$\therefore\tan\alpha = \frac{H}{R/2}$
$= \frac{\frac{u^{2}}{4g}}{\frac{u^{2}}{2g}} = \frac{1}{2}\ \therefore\ \alpha = \tan^{- 1}\left( \frac{1}{2} \right)$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.