An elevator moving up with a constant speed 20  m/s. A coin is dropped from a height of 125 m inside the elevator .The time taken by coin  to reach the floor of elevator  is g=10m/s2

initial relative velocity  of coin with respect to elevator uce =0Displacement of coin with respect to elevator sce =125 mrelative acceleration of coin with respect to elevator ace =10-0 =10m/s2t=?we know Sce=Ucet+12acet2substitute the values obtained,125=0+12(10)t2250=10t2⇒t=5sec=time in which coin reaches the floor of elevator