Actually, I should idiot proof the above a bit more for John:

MR HELMET, YOU HIT HIM AT 10MPH AND HIM SQUASH BUT NOT BREAK, YOU MEASURE SQUASHINGNESS SO CAN LOOK UP SQUASHINGNESS AT 10MPH!

MR HELMET, YOU HIT HIM AT 15MPH AND HIM SQUASH BUT NOT BREAK, YOU MEASURE SQUASHINGNESS SO CAN LOOK UP SQUASHINGNESS AT 15MPH!

MR HELMET, YOU HIT HIM AT 20MPH AND HIM BREAK, YOU KNOW HIM BREAK AT 20MPH!

IT NOT ROCKET SCIENCE! (YOU HIT HELMET WITH ROCKET IT CAN BE ***VERY*** BAD! BE CAREFUL OF TYPOING AND USE ***ROCK*** INSTEAD!)