06 - Slow In & Slow Out

http://www.danrstack.com/twelve/

A movement does not happen at a constant speed from start to finish. Objects take time to accelerate and slow down. As an action starts, there are more frames near the starting pose, a few in the middle, and more near the end pose. More frames near the beginning and end will make the object seem heavier, and fewer will make it seem lighter. When a car comes to a stop, it has to apply the brakes and slow down before eventually stopping. When a car begins to move, it has to accelerate out of the static pose.