Pulley System with 18-1 Weight Reduction

This demo is not used to teach elementary principles (the analysis of it is quite tedious), but instead is used to illustrate an extreme example of
mechanical advantage.

9 coupled pulleys are linked together to reduce the effective weight felt by an observer, when they pull on the string. As each coupled pulley pair
reduces the felt tension from T -> T/2, the theoretical reduction in weight is a factor of 18.

In the demo, 3kg of mass is added to the bottom of the pulley system. The theoretical weight felt by an observer is 3000g / 18 = 166g.

The system was measured with a force sensor, and a reduced weight of around 210g was recorded (it is higher due to frictional effects present in the system).

Get the students to hold 3kg of mass, and then pull on the string to illustrate the mechanical advantage that is taking place.