Equilibrium of moments on pulleys (TM121)

Equilibrium of moments on pulleys (TM121)

memorable demonstration of the equilibrium of moments



  • The TM 121experimental unit illustrates the laws for forming the equilibrium of moments in static systems.
  • The relations between wheel diameter, moment and circumferential force are demonstrated.
  • Two pulleys with different diameters are mounted on a steel shaft, which is itself mounted on ball bearings.
  • Weights can be hung on the cables, making it possible to represent different load cases acting on two pulleys with different diameters.
  • The forces can be varied using weights until equilibrium is reached.
  • The experimental unit is designed to be fixed to a wall.
  • The parts of the experiment are clearly laid out and securely housed in a storage system.

Technical Details:


  1. investigation of the equilibrium of moments on two pulleys
  2. anodised aluminium pulleys
  3. ball bearing-mounted steel shaft
  4. storage system for parts
  5. bracket for wall mounting

Technical Data:


  • Ø=75mm
  • Ø=150mm


  • 2x 1N (hanger)
  • 4x 0,5N
  • 4x 1N
  • 4x 2N
  • 4x 5N

Base plate:

  • W x H: 200x250mm

Dimensions & Weight:

  • L x W x H: 250x200x250mm
  • Weight: approx. 13kg
  • L x W x H: 290x140x130mm (storage system)

Learning Objections/Experiments:

  • fundamentals of the equilibrium of moments: acting forces, generated moments and equilibrium
  • effect of forces as a function of pulley diameter

Scope of Delivery:

  • 1 experimental unit
  • 1 set of weights
  • 2 cables
  • 1 set of instructional material


  • direct indication of shear force and bending moment at a section on the beam


Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.