WAEC Physics 2010 Theory — Question 13

Model answer

Perfectly Elastic Collision: (i) Directions of the bodies are reversed (in a head-on collision). (ii) Kinetic energy is conserved. (iii) Colliding bodies do not stick together after collision. Perfectly Inelastic Collision: (i) Directions of bodies are not necessarily reversed. (ii) Kinetic energy is not conserved (it decreases). (iii) Colliding bodies stick together and move as a unit with the same velocity after collision.