Two particles moving initially in the same direction undergo a one- dimensional , elastic collision . Their relative velocities before and after the collision are `vec(v_(1))` and `vec(v_(2))`. Which of the following is not correct?

Options

A. `|vec(v_(1))|=| vec(v_(2))|`
B. `vecv_(1)=-vecv_(2)` only if the two are of equal mass.
C. `vecv_(1).vecv_(2)=-|vecv_(1)|^(2)`
D. `|vec(v_(2)).vec(v_(1))|=|vec(v_(2))|^(2)`

Answer

B