Question

the time flight of a projectile is related to it it's horizontal range by the equation gT² = 2R the angle of projection is?

Answer 1

$T=\frac{2v\sin\alpha}{g},$

$R=\frac{2v^2\sin\alpha \cos\alpha}{g},$

$gT^2=2R,$

$\frac{4gv^2\sin^2\alpha}{g^2}=\frac{4v^2\sin\alpha\cos\alpha}{g},$

$\sin\alpha=\cos\alpha,$

$\alpha=45°.$