Periodic motion is motion that repeats itself in regular intervals. If the motion has characteristics that are sinusoidal, then the motion is said to be simple harmonic (SHM). In this lesson, periodic motion that is not simple harmonic is studied. Never-the-less, the motion shows many characteristics of SHM, as can be seen when studying the position, velocity, and acceleration graphs. This lab makes use of PocketLab Voyager that has hitched a ride on an "intelino smart train" and is running on the VelocityLab app. Intelino is designed for all ages, has an intuitive app, has built-in sensors to provide an interactive experience for the user, and is easily programmed with color snaps that allow the user to control intelino's actions.
The PocketLab Voyager/intelino Periodic Motion Lab Setup
Voyager is attached to a measuring wheel with a 3M damage-free strip in the orientation shown in Figure 1. The measuring wheel consists of a pair of 3D printed wheels with rubber band tires, an axle, and a hitch. STL files are included with this lesson for the wheels, axle, and hitch. The hitch is attached to the intelino engine with a 3M damage free strip. The front of the intelino engine faces to the right. The weight of the measuring wheel plus Voyager is less than that of a pair of intelino wagons.
Intelino will go back and forth between a pair of reverse color snap commands, providing the periodic motion. For best results, the pair of color snap commands should be placed between 50 and 60 cm apart, and the engine should be running at the intelino autopilot speed "fast".
VelocityLab requires input on the diameter of the wheel to which Voyager was attached. This value, after adding the rubber band tires to the 3D printed wheel, was 6.5 cm. The z-axis is specified as the "axis of rotation" in the VelocityLab app. Make sure to orient Voyager to the wheel as shown in Figure 1, with the orange side of Voyager facing the wheel.