Promotes understanding of basic concepts of mechanics including equilibrium, resolution, and composition of forces, levers, inclined planes, pulleys, friction, etc.
This demonstration needs two equal weights hanging by threads, and two more threads with handles suspended below. Pulling down with an even force or with a jerk causes the upper or lower string to break respectively.
Center of Mass
Three demonstrations are available: bear on a string, center of mass “bird”, and center of mass forks.
Finding the Center of Mass for Irregularly Shaped Objects
This blackboard demonstration uses a plumb line to find the center of mass for either a cardboard “amoeba” or a plastic polygon.