A body projected from a height 60 m with a velocity 10 m/s at an angle 300 above the horizontal. The time of flight of the body is g=10m/s2 ….

Initial vertical velocity  =10sin300=5m/s(upwords)Displacement of the body is  s=60m(downwords)−s=ut−12gt2 −60=5t−12×10×t2 t2−t−12=0 t(t−4)+3(t−4)=0 t=4s