The path followed by a body projected along y-axis is given as by y=3x−1/2x2,if g = 10 m/s2, then the initial velocity of projectile is (x and y are in m)

On comparing the coefficient of x2 in the given equation with the standard equation, we gety=x tan θ−gx22u2cos2θ   tanθ=3,θ=600 ⇒g2u2cos2θ=12Substituting θ = 60°, we get u=210 m/s.