MCQ
If $R$ and $H$ represent the horizontal range and the maximum height achieved by a projectile then which of the relation exists?
  • A
    $\frac{H}{R} = 4\,\cot \,\theta $
  • $\frac{R}{H} = 4\,\cot \,\theta $
  • C
    $\frac{H}{R} = 4\,\tan \,\theta $
  • D
    $\frac{R}{H} = 4\,\tan \,\theta $

Answer

Correct option: B.
$\frac{R}{H} = 4\,\cot \,\theta $
b
$\begin{array}{l}
R = \frac{{{u^2}\sin 2\theta }}{g} = \frac{{2{u^2}\sin \theta .\cos \theta }}{g}\\
H = \frac{{{u^2}{{\sin }^2}\theta }}{{2g}}\\
\therefore \,\frac{H}{R} = \frac{{{u^2}{{\sin }^2}\theta }}{{2g}} \times \frac{g}{{2{u^2}\sin \theta .\cos \theta }}\\
\,\,\,\,\,\,\,\,\,\,\, = \frac{{\sin \theta }}{{4\cos \theta }}\\
 \Rightarrow \frac{R}{H} = \frac{{4\cos \theta }}{{\sin \theta }}\,or\,,\,\frac{R}{H} = 4\cos \theta 
\end{array}$

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