Question

A ball is thrown from the ground to clear a wall $3\text{m}$ high at a distance of $6\text{m}$ and falls $18\text{m}$ away from the wall, the angle of projection of ball with horizontal is

• A. ${\tan }^{-1}\left(\frac{3}{2}\right)$
• B. ${\tan }^{-1}\left(\frac{2}{3}\right)$
• C. ${\tan }^{-1}\left(\frac{1}{2}\right)$
• D. ${\tan }^{-1}\left(\frac{3}{4}\right)$

Answer 1

The correct option is B ${\tan }^{-1}\left(\frac{2}{3}\right)$


From equation of trajectory $y=x\tan \theta [1-\frac{x}{R}]\Rightarrow 3=6\tan \theta [1-\frac{1}{4}]\Rightarrow \tan \theta =\frac{2}{3}$