Question: One of Sarah's neighbors spilled dog food all over the stairs. The dog food pieces are on three stairways and all over the landings. Sarah gets mad and kicks a piece of dog food. The dog food flies across the wooden planks from one side of the staircase landing to the other which was 4 meters long. The dog food reaches the neighbor's door mat. It just moves 0.2 meters across the doormat and then stops. Why didn't the dog food move further across the doormat?? 
Option 1: The door mat is a spikier surface
Option 2: the staircase landing is a spikier surface
Answer: Option 1