Question

When air resistance can be neglected, the maximum range of a projectile is achieved for what launch angle? (in degrees)

• A. $90$
• B. $45$
• C. $30$
• D. $60$

Answer 1

The correct option is B $45$

The range of a projectile is given by $R=\frac{u^2\sin 2\theta }{g}$

where $u$ is the projected velocity and $\theta$ is the angle with horizontal.

So, for maximum range R, we must have $\sin 2\theta =1$

or $\sin 2\theta =\sin 90$

or $2\theta ={90}^o$

$⟹$ $\theta ={45}^o$