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

Options

A. 9.9 m
B. 10.0 m
C. 10 m
D. 20 m

Answer

B

Explanation

(b) As there is no external force acting on man, initially the centre of mass of the system was at rest hence there is ni displacement of centre of mass.
`m Delta r = constant`
`m_1 Delta r_1 = m_2 Delta r_2`
`rArr Delta r_2 = (m_1 Delta r_1)/(m_2) = (0.5 xx 10)/(50) = 0.1 m`
The distance of the man above the floor (total hight)
=`10 + 0.1 = 10.1 m`.