31 ) As u = 0  &  elevator descends downward  implies coin has to move more distance than 1.8 m to strike the floor  & T = 1 sec.  S_c = ut + 0.5*at² = 0 + 1/2 g(1)² = 0.5 g   &   S_e = ut + 0.5*at²   =   u + 0.5 a(1)² = 0.5 a  Total distance covered  1.8 + 0.5 a = 0.5 g  therefore  1.8 + 0.5a = 0.5 g implies  a = 6.2 m/s² = 6.2 × 3.28 = 20.34 ft/s².