In this tutorial, you will calculate an estimate for how many electrons were transferred from one tape to the other in the charging process. This analysis will require making assumptions that are valid for getting an order of magnitude estimate, and then making sense of this number. Make sure you submit answers with at least three significant figures. Let's begin. First, we want to levitate one tape below the other. One way to do this is to prepare a U-Tape and a L-Tape according to the procedure used in the lab. That is, starting with two tapes attached and neutral and pulling them apart. Now you have two oppositely charged tapes that are attracted to each other. Although it is practically very difficult to perform this trick, we can work through a thought exercise which will ultimately lead to a result for determining the number of electrons transferred. Start with both tapes horizontal and far apart. Slowly bring the top tape closer to the bottom tape by lowering the top tape. The tape above will provide an upward electrostatic force on the bottom tape. The closer the tapes, the greater this upward force. So there exists a distance d where the upward electrostatic force on the bottom tape results in a net force equal to zero. (Again difficult to do, because getting too close causes the lower tape to accelerate upwards)