Q2 of 8 Page 178

Two particles A and B initially at rest move towards each other mutual force of attraction. At the instant when the speed of A is V and speed of B is 2V, the speed of centre of mass is?

Let,

Mass of particle


Mass of particle


Initial speed of particle


Initial speed of particle


Final speed of particle


Final speed of particle


Given, initially both the particles at rest, so,




Given, at some instant of time,




We Know, speed of centre of mass at any instant is




Since no external forces act we apply conservation of linear momentum,




Using,



In expression of VCM, we get,



Hence, speed of centre of mass is zero.


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