Blended Learning Lesson 8 Dynamics 4: Collisions I figured it out already. Need three laws only.

Principle of Conservation of Momentum The total linear momentum of a system is conserved if no net external force acts on the system.

4.8.1 Head-on vs Glancing Collision A head-on collision is one in which the directions of motion before and after the collision are along the same line of motion. uv1v1 v2v2 beforeafter Head-on Collision u v1v1 v2v2 beforeafter Glancing Collision

4.8.2 Elastic vs Inelastic Collisions An elastic collision is one all the kinetic energy is conserved. An inelastic collision is one whereby there will be a lost in kinetic energy. A perfectly inelastic collision is one where the 2 objects coalesce (stick together) and move with common velocity after the collision. Note: A perfectly elastic collision represents the maximum possible loss of kinetic energy. It does NOT necessarily mean all the KE is lost.

Elastic Collision

Inelastic Collision

Relative Velocity With respect to BLUE sphere (i.e. from the frame of the blue sphere)

V A =V B after collision (maximum loss in KE) Total Initial KE = Total Final KE Total Final KE < Total Initial KE (KE converted into internal energy, deformation energy, etc) Relative speed of approach = relative speed of seperation