Situation 1: A 300 gram chunk of clay is thrown at a door with a velocity of 10 m/s. The clay sticks to the door. Determine whether the interaction is elastic. Hint: determine the initial kinetic energy and the final kinetic energy.
Situation 2: A 300 gram bouncy ball is thrown at a wall with a velocity of 12.2 m/s and bounces back with a velocity of 11.6 m/s. Is the interaction elastic?