This is an interactive educational project showing the relationship between the movement around a circle (circular motion) and the movement of an object attached to a spring (harmonic motion). Instructions: Up/down keys (keep pressed) to rotate the circle. Space to switch 3D lighting on/off (visible when the circle is almost flat). The red circle is vertical at startup. You can make it horizontal/vertical by down/up keys. The green dot moves at a constant speed along the circle (that is, with a uniform circular motion). When the circle is horizontal I suggest to switch lighting off. The green dot moves now with an harmonic motion with respect to the red line segment, that is more slowly when it is close to the end points and more quickly when it is closer to the middle of the line segment. This is a "harmonic motion"
Thanks to @Blue-Monkey for the 3D circle drawing script. FEATURED on 24/7/2015: thank you guys! Updates: 25/07: added "go to front" for splash screen (suggested by @IAP-Reloaded) 25/07: added splash screen 20/07: added circular/linear speeds (linear speed visibile only when the circle is flat) 20/07: cleaned code