Question

A particle moves under gravity such that at any time $t$ the vertical and horizontal position from projection point are given as $y=(10t-5t^2)$ and $x=\left(10\sqrt{3}t\right)$ respectively. Then angle of projection with horizontal is:-

• A. ${60}^{\circ }$
• B. ${30}^{\circ }$
• C. ${45}^{\circ }$
• D. ${75}^{\circ }$

Answer 1

The correct option is B ${30}^{\circ }$

$y=10t-5t^2\Rightarrow u\sin \theta =10t$

$x=10\sqrt{3}t\Rightarrow u\cos \theta =10\sqrt{3}$

$\Rightarrow \tan \theta =\frac{1}{\sqrt{3}}$

$\Rightarrow \theta ={30}^0$

Hence,

option $\left(B\right)$ is correct answer.