Gear train
Imagine the three circles in the left hand panel are three meshing gears.
You can move the entire gear train by dragging the large BLUE dot.
[You can also animate the motion.]
How are the radii of the three gears related?
How are the angular velocities of the three gears related?
How are the linear speeds of BLUE, YELLOW & GREEN dots related?
How would you introduce the practical uses of gear trains to your students?
What other questions could/would you ask of your students based on this applet?