Conservation of Linear Momentum Practice Test

Two identical carts on a frictionless track interact via a compressed spring. Initially, both carts are at rest and the spring is compressed between them; the system is the two carts (ignore the spring’s mass). External forces on the system are negligible. After release, cart 1 moves left at $3.0,\text{m/s}$. What is the velocity of cart 2?

A $3.0,\text{kg}$ cart moving right at $2.0,\text{m/s}$ collides and sticks to a $1.0,\text{kg}$ cart initially at rest on a frictionless track. The system is both carts, and external forces are negligible during the collision. What is the final velocity of the combined carts?