1. 9.8 Momentum and Kinetic Energy in Collisions
The linear momentum is conserved for collisions in a closed and isolated system.
In an elastic collision, the total kinetic energy is conserved.
In an inelastic collision, the total kinetic energy is not conserved.
In a completely inelastic collision, the colliding objects stick together, after the collision.
What is the second object for the collisions shown in the figure?

2. 9.10 Elastic Collisions in One Dimension
Stationary Target. Closed & Isolated system. Momentum & Kinetic Energy are conserved.

3. 9.11 Collisions in Two Dimensions

4. 9.12 Systems with Varying Mass: A Rocket
Problem 76:A 6090 kg space probe moving nose-first toward Jupiter at 105 m/s relative to the Sun fires its rocket engine, ejecting 80.0 kg of exhaust at a speed of 253 m/s relative to the space probe. What is the final velocity of the probe?