Question

A projectile is thrown in to space so as to have the maximum possible horizontal range equal to $400m$. Taking the point of projection as the origin, the coordinate of the point where the velocity of the projectile is minimum are

• A. $(400,200)$
• B. $(200,200)$
• C. $(400,100)$
• D. $(200,100)$

Answer 1

The correct option is D $(200,100)$

$400=\frac{u^2\sin 2\theta }{g}(\theta ={45}^0$ for maximum range)

$[\frac{u^2}{g}=400]$.....(1)
$H_{max}=\frac{u^2{\sin }^2\theta }{2g}=\frac{u^2}{4g}=\frac{400}{4}=100$ m

minimum velocity is at top most point = 100 m

Range during that instant $=\frac{Range}{2}$
$=400/2=200$
$\Rightarrow$ (200,100) is coordinate of the point
Option D is correct.