The Physics behind Kiss Me Kate

This weekend was the culmination of work for the cast, crew and pit of the spring Musical Kiss Me Kate. AS a member of the crew it was my job to make the magic of the show happen for the cast to shine in their full glory. For some of the times that required being on fly rail (the part of the theatre that manually pulls in and out the drops that come onto stage.) Now mind you I shared this task with a less experienced whiny senior. But the physics for moving the these set pieces remain the same on the stage or above. On the stage there are the two big rolling pieces which require a Strong force to overcome static friction of the wheels. The wheels make the job a lot easier because they have a smaller static coefficient and can glide across the floor quicker in the dark.

The second part of the theatre magic is in the fly rails. These thousand pound drops experience a large weight force and have a lot of potential energy being raised about 20 meters up.

To assist with lifting these beautiful drops, we have a combination pulley system assisted by weights. A combination pulley system is comprised of a stationary pulley and a movable pulley, which in this case has weights on it to decrease the weight we are actually pulling. Since there are only one complete set of pulleys, we halve the difference between the weight of the drop and the weight of the weights. The overall force we had to move is supplied by the rope via tension to life the drops in and out.

This is the magic of the theatre.