Question

a block of mass 3m ans fast

Answer 1

when man starts to climb block he pushes block backward hence block also pushes man forward according to the Newton's third law of motion . If we assume man + block system then ,
Fnet = 0 then ,
according Newton's first law of motion , acom = 0
when acceleration is zero means there is no change in the velocity i.e Vcom =
constant

but ,Vicom = 0
Vfcom = 0
if Vfcom = 0 then there no change in the displacement of system I. e there is no displacement of centre of mass of man + block system hence ,
option C) is right answer .

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here ,
com - center of mass