Three experiments on the Einstein's lift

We propose a didactic model of Einstein's lift used to show the physics in a freefalling frame of reference. We discuss three experiments in Einstein's lift: the spring-mass system, the two repelling magnets system and the pendulum oscillations in free fall. Measurements are carried out through analysing videos acquired using a digital camera by means of open-access video analysis software which allows to describe the motion in both the inertial and moving frames of reference. We also show some videos edited with the software Adobe After Effects which enable us to see what happens in a freefalling frame of reference, and a video acquired by a GoPro camera falling integral with the lift. The topic, the accessibility of the experiments and the level of analysis are appropriate for an undergraduate classical mechanics course.