Some time ago, Tim Folkerts of Barton Co. CC, Great Bend, KS, posted a note on one of the physics internet discussion groups about juggling on a Force Plate. He even collected data on the apparent “weight” of jugglers as they perform. Well, it turns out Vernier Software & Technology has its own juggler, Scott Van Hoosen. We had Scott try this experiment with three balls and then five balls.

For each trial, Scott first held the objects in his hands, and then started juggling. Note that the average force reading remains about constant, but there is more deviation of the readings with the five balls (He throws the balls higher when using five balls).
Download a movie and sample data