An object is projected upward with a velocity of 100 m/sec. It wilt strike the ground in approximately

Let f be the time taken by the object to reach maximum height where v - 0. Hence,0=100-10 x t1 or t1 = 10secFurther (0)2 =(100)2 -2 x 10 x /hor h= 500mLet t2 be the time taken by the object to strike the ground.Then500=0×t2+12×10×t22 or t2=10secTotal time t =t1 - t2 = 20 sec