An elevator moving up with a constant speed 20 m/s. A coin is dropped from a height of 5 m inside in the elevator  the time, it reaches the floor of elevator is  g=10m/s2

relative initial velocity of coin with respect to elevator=Uce=Uc−Ue=10−10=0  Sce=5m =  Displacement  of  coin with respect to elevator relative acceleration of coin with respect to elevator=ace=ac−ae=10−0=10m/s2.t=?  From  relative displacemet of coin with respect to elevator=Sce=Ucet+12acet2 5=0+1210t210=10t2⇒t=1sec=time taken by coin to reach the floor of the elevator