Question

The launching speed of a certain projectile is five times the speed which it had at it's maximum height. It's angle of projection is

• A. $\theta =co{s}^{-1}\left(0.2\right)$
• B. $\theta =si{n}^{-1}\left(0.2\right)$
• C. $\theta =ta{n}^{-1}\left(0.2\right)$
• D. $\theta =0^o$

Answer 1

The correct option is A $\theta =co{s}^{-1}\left(0.2\right)$

At maximum height, horizontal component of velocity is $vcos\theta$, while vertical component of velocity is $0$.
$\Rightarrow v=5vcos\theta$
$\Rightarrow \theta =co{s}^{-1}\left(\frac{1}{5}\right)=co{s}^{-1}\left(0.2\right)$