Projectile is the form of the motion that is experienced by the object thrown near the surface of the earth.
The displacement of the object at any timetwill have both component i.e. x and y
x=utcosθ (1)
y=utsinθ−12gt2 (2)
The magnitude of the displacement is given as
Δr=√x2+y2
Substitute the value oft from equation(1)in equation(2)we get
y=tanθ⋅x−g2v20cos2θ⋅x2
Whose generalised form is given as,
y=ax+bx2
Hence the equation of the projectile is the parabola.