The equation of trajectory of a projectile fired horizontally from a tower with Velocity U is given by:(Take vertically upward as + Y- axis and horizontal as X-axis )

let horizontal component of velocity of body projected horizontally be u=ux vertical component of velocity of body=uy=0 after time t second,  displacement of the body along horizontal is x =uxt⇒t=xux---(1) displacement of the body along vertical is y=uyt+12(-gt2)=0+12(-gt2)---(2) substitute equation (1) in (2) y=-12gxux2=-12gxu2 this equation is in the form of y=kx2 which represents equation of a parabola