## Class/Course - Class XI

### Subject - Physics

#### Chapter - Scalar and Vector

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 Dear User, Kindly login/register to view answer & explanation of each question. Click here to Login/Sign Up. Q.1 Two point masses 1 and 2 move with uniform velocities $\vec{v}_{1}$ and $\vec{v}_{2}$, respectively. Their initial position vectors are $\vec{r}_{1}$ and $\vec{r}_{2}$, respectively . Which of the following should be satisfied for the collision of the point masses? $\frac{\vec{r}_{1} - \vec{r}_{2}}{\left | \vec{r}_{2} - \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} - \vec{v}_{1} \right |}$ $\frac{\vec{r}_{2} - \vec{r}_{1}}{\left | \vec{r}_{2} - \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} - \vec{v}_{1} \right |}$ $\frac{\vec{r}_{2} - \vec{r}_{1}}{\left | \vec{r}_{2} + \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} + \vec{v}_{1} \right |}$ $\frac{\vec{r}_{2} + \vec{r}_{1}}{\left | \vec{r}_{2} + \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} + \vec{v}_{1} \right |}$