RipStik forces, Hooke's law

Coverage of 051 included the calculation of the force required to accelerate a RipStik. Data was gathered two days earlier.




The starting concrete post is actually the second one from the east end of the building. The distance between the easternmost pillar and the next pillar is less than 4.6 meters due to a stairwell on the end of the building, as can be seen in an image from last January.






  • The distance increases non-linearily with time due to the non-zero acceleration.
  • The constant acceleration, or rate of increase of velocity with respect to time, was 0.12 m/s²
  • From the start to the first post my intent was to maintain the lowest possible speed without
  • falling off the RipStik.Thus the bulk of the acceleration across this segement is the
  • initial acceleration from rest.
  • At the first concrete post I began to increase my speed as gradually as I could.
  • As I moved along the walkway I was unintentionally increasing my rate of acceleration until
  • the fourth post.
  • After the fourth post I eased off on the forces I was exerting as I prepared to dismount from
  • the RipStik.

Laboratory 52 then focused on Hooke's law. This laboratory was also modified this summer. After averaging 30 marbles and finding an average mass of just over five grams, I asked the class to use five grams as the mass of one marble, or a force of five gram-force per marble.


Most schools here lack triple beam mass balances. Yet this experiment can be done without a beam balance by simply assigning a mass to the marbles. 

Maureen and Randy adjust their cup to hang at one meter above the table.

Hattie and Mylee.

Edmund and Hedges.
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