Question

Two particles of equal mass have coordinates (2m,4m,6m) and (6m,2m,8m). Of these one particle has a velocity `v_(1) = (2i)ms^(-1)` and another particle has a velocity `v_(2) = (2j)ms^(-1)` at time t=0. The coordinate of their center of mass at time t=1s will be
A. (4m,4m,7m)
B. (5m,4m,7m)
C. (2m,4m,6m)
D. (4m,5m,4m)

Answer 1

Correct Answer - B
After 1s, coordinates of first particle will become (4m,4m,6m) and coordination of second particle will become (6m,4m,8m).
`therefore` `X_(CM) = (4+6)/(2) = 5m`
`Y_(CM) = (4+4)/(2) = 4m` and `Z_(CM) = (6+8)/(2) = 7m`
Note. In this particle answer is independent of the fact whether the first particle has velocity `v_(1)` or `v_(2)`. Think why?