Equation of trajectory of a particle projected from a point on ground is y=x−x2240where x and y are in metre. If g=10m/s2, velocity of projection is

y=x1−x240Comparing this equation with the standard equation y=xtanα1−xR, We gettanα=1⇒α=450and Range = 240 mNow u2gsin2α=240⇒u210sin(2×450)=240⇒u=206m/s