A man of 50 kg mass is standing in a gravity free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed of 2 ms-1. When the stone reaches the floor, the distance of the man above the floor will be

As there is no external force acing on man, initially the center of mass of the system was at rest hence there is no displacement of center of mass.   [m1+m2] ∆rcom=0   m 1∆r1 - m2∆r2 =0⇒  ∆r2 = m1∆r1m2 = 0.5×1050 = 0.1 mThe distance of the man above the floor (total height) = 10+0.1 = 10.1 m