Two frictionless trolleys travel towards one another on the same horizontal straight line. Their masses and velocities are given. The trolleys collide and remain joined together. What is the velocity of the trolleys after the collision?
- A$2.0\,\text{m s}^{-1}$ to the left
- B$2.0\,\text{m s}^{-1}$ to the right
- C$2.8\,\text{m s}^{-1}$ to the left
- D$2.8\,\text{m s}^{-1}$ to the right