Question

If equation of a projectile is Y=12x-3/4x^2

Answer 1

y=12x-3/4x^2. The simplest way to calculate the range is to put y=0 in the equation of parabolic trajectory. This gives

12x-3/4x^2=0. Therefore,

x(12–3/4x^2)=0. Then,

x=0 gives x coordinate of the point of projection and

12=3/4x or x=16 m gives the range of the projectile.

Answer 2

$eq. \: of \: trajectory \\ \\ \\ y = x \tan( \alpha ) - \frac{g {x}^{2} }{2 {u}^{2} { (\cos( \alpha ) )}^{2} }$
by this we get

$\tan( \alpha ) = 12$
and by same comparing we can get velocity