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. `20m`
B. `9.9m`
C. `10.1m`
D. `10m`

Answer

c

Explanation

Here, `m_(1) = 50 kg, m_(2) = 0.5kg, upsilon_(2)m//s`
`S = 10 m, upsilon_(1) =`?
From the coservation of liner momentum
`m_(1) upsilon_(1) = m_(2) upsilon_(2)` Therefore `50 xx upsilon_(1) = 0.5 xx 2`
`upsilon_(1) = (1)/(50)m//s`
Time taken by the stone to cover the distance of `10m` and reach the floor (in gravity free space)
` t = (S)/(upsilon_(2) = (10)/(2) =5s`
distance covered by the man (in the opposite direction) in `5 sec = upsilon_(1) xx t = (1)/(5) xx 5 =0.1m`
Distance of the man above the floor
`= 10+ 0.1 = 10.1m` .