Conservation of Momentum
Drill a hole in the soft ball and screw the eye bolt in it. You may want to place some glue on the eye bolt before screwing it in. Tie a string on the end of it. you can tie the string on the supports that hold the ceiling tiles in place or look under your ceiling tiles. In most of the schools there are steel beams that support the ceiling there. tie the string there. this is nice as when you are done , you can place the pendulum in the ceiling and hide it there until you are ready to use it next year. I label the tiles so i know where these are hidden in the room. You need to measure the string so that it reaches your chin .
Raise the ball to your chin. Release the ball. DONOT LEAN FORWARD. The ball will come very close to your chin but will not hit it. You can feel air resistance slowing the ball up on your face. Students will think you be hit in the face. the ball will not gain energy so it will not hit you in the face. The energy changes form with the resistance of the air and the resistance with the string.
Note Shopko often puts softballs on sale for a $1.00 to $1.50 in September.
