On a youtube channel that you may have all seen at one time or another they have made a video about throwing a soccer or football at somebody's face. This channel, called The Slow Mo Guys, records things in slow motion. In this video they show a face getting hit by a soccer ball in supper slow motion. The cool thing about this is that you can see the inertia that the head holds and its resistance to movement from the soccer ball. The other cool thing that you can see in super slow motion is that the energy the ball has goes from kinetic energy, as its moving, into potential energy, as the air inside is compressed as the ball is mushed against the head.