Answer:
45°
Explanation:
The horizontal displacement of any projectile (assuming the it is launched from the same height as it arrives) is given by:
[tex]X = \frac{2*V^2}{g}*cos\alpha *sin\alpha[/tex]
As you can see it depends on both the sine and cosine of the launch angle.
When you graph that multiplication (cos(α) * sin(α)), you can see that it has a maximum peak at [tex]\alpha =45\°[/tex] (shown in the picture)
You could also derive the expression and find its maximum but I'll leave that for another time.
