MCQ
A smooth sphere is moving on a horizontal surface with velocity vector $3 \hat i + \hat j$ immediately before it hits a vertical wall. The wall is parallel to the vector $\hat j$ and the coefficient of restitution between the wall and sphere is $\frac{1}{3}$. The velocity vector of the sphere after it hits the wall is
- A$\hat i + \hat j$
- B$3 \hat i - \frac{1}{3} \hat j$
- ✓$-\hat i + \hat j$
- D$\hat i - \hat j$
