Two persons of masses `55 kg` and `65 kg` respectively are at the opposite ends of a boat. The length of the boat is `3.0 m` and weights `100 kg`. The `55 kg` man walks up to the `65 kg` man and sits with him. If the boat is in still water the centre of mass of the system shifts by.

Options

A. `0.75 m`
B. `3.0 m`
C. `2.3 m`
D. zero

Answer

D

Explanation

As there is no external force acting on the boat, so, centre of mass will not shift. Initially `vecV_(cm)=0`
`vecF_(ext)=0`
`mveca_(cm)=0" "impliesveca_(cm)=0`
`DeltavecV_(cm)=0`
(this means centre of mass remains the same)
`(dvecr)/(dt)=0`
`impliesvecv_(cm)=` cosntant or displacement of centre of mass is zero.