16.A drunkard is walking along a straight road. He takes 5 steps forward and 3 steps backward, followed by 5 steps forwards and 3 steps backward and so on. Each step is one metre long and takes one second. There is a pit on the road 11 metre away from the starting point. The drunkard will fall into the pit after

17.Two bodies begin a free fall from rest, the same height, 1 second apart. How long after the first body begins to fall will the two bodies be 10 apart ?

18.A ball released from a certain height falls 5 m in one second. In 4 s it falls through

19.A particle starting from rest travels a distance x in first 2 second and a distance y in next 2 second, then

20.A dust packet is dropped from 9th storey of a multi-storeyed building. In the first second of its free fall another dust packet is dropped from 7th storey 15m below the 9th storey. If both packets reach the ground at same time, then height of the building is: