Two particles A and B, move with constant velocities o V1 and v2. At the initial moment their position vectors are r1 and r2 respectively. The condition for particles A and B for their collision is:

Q. Two particles 'A' and 'B', move with constant velocities $\overrightarrow{v_1}$ and $\overrightarrow{v_2}$ respectively. At the initial moment, their position vectors are $\overrightarrow{r_1}$ and $\overrightarrow{r_2}$ respectively. The condition for particle 'A' and 'B' for their collision is

Q. Two particles A and B, move with constant velocities $\overrightarrow{v_1}$ and $\overrightarrow{v_2}$. At the initial moment their position vectors are $\overrightarrow{r_1}$ and $\overrightarrow{r_2}$ respectively. The condition for particles A and B for their collision is:

Q. Two particles 'A' and 'B', move with constant velocities $\overrightarrow{v_1}$ and $\overrightarrow{v_2}$ respectively. At the initial moment, their position vectors are $\overrightarrow{r_1}$ and $\overrightarrow{r_2}$ respectively. The condition for particle 'A' and 'B' for their collision is

Q. Two particles, $1$ and $2$ moves with constant velocities $v_1$ and $v_2$. At the initial moment their radius vectors are equal to $r_1$ and $r_2$. How must these four vectors be interrelated for the particles to collide.

Q. Two point masses $1$ and $2$ move with uniform velocities $v_1$ and $v_2$ respectively. Their initial position vectors are $r_1$ and $r_2$, respectively. Which of the following should be satisfied for the collision of the point masses?