Question

Two particles of masses 4 kg and 8 kg are separated by a distance of 12 m. If they are moving toward each other under the influence of a mutual force of attraction, then the two particles will meet each other at a distance of

• A. 6 m from 8 kg mass
• B. 2 m from 8 kg mass
• C. 4 m from 8 kg mass
• D. 8 m from 8 kg mass

Answer 1

The correct option is D 8 m from 8 kg mass

Mutual force is nothing but an $internal$ force, so the position of the $center$ of mass $should{n}^{\prime }t$ change.

Position of the center of mass from mass $4kg$ will be $\frac{4}{4+8}12meter=4meter$ so at a distance $d=12m-4m=8m$ from $8Kg$ mass.

They need to move to the position of center of mass.