Reference: M68
Category: Mechanics
Purpose: Illustrates Newton's 1st law in a less intuitive setup.
Description: Two equal masses hang over a double pulley at rest. When they are set in motion vertically they slide up or down at a constant speed since the forces acting on them are balanced. A fun thing to ask the class is what happens to the other mass (moves up or down) if one mass is allowed to swing like a pendulum.
