Discover Centripetal Force Kit

Product Code: ME-9837A


The Discover Centripetal Force Kit demonstrates the change in centripetal force as key variables are manipulated. A range of rubber stoppers are included to allow mass to be varied widely. Convenient plastic ties are used to easily secure the swinging masses to the string.

Three experiments can be conducted:

  • Force vs. Speed: vary the speed of the stopper; hold mass and radius constant
  • Force vs. Radius: vary the radius of the path; hold speed and radius constant
  • Force vs. Mass: vary the mass of the stopper; hold speed and mass constant


  • Rubber Stoppers (sizes 6, 8, 10)
  • Plastic Ties (10)
  • Yellow String (73 meters)
  • Hollow Tube

How It Works

Designed around the classic PSSC experiment, students hold the metal tube and swing the rubber stopper overhead. The rubber stopper moves in a circular path while the other end of the string is connected to a hanging mass. Since the system is in equilibrium, the centripetal force is equal to the weight of the hanging mass.

Once the swinging mass is moving with constant speed, another student uses a stopwatch to time the period of one revolution. Students also measure the radius of the circular path, allowing them to calculate the speed of the rubber stopper by dividing the circumference by the period.

This experiment can also be made to be quantitative and dynamic by integrating a force sensor, motion sensor and PASCO software and interfacing.

Support Documents

Discover Centripetal Force Kit Manual