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The sling

The sling
Materials and mounting
instructions:
  a robust Y-shaped stick, a rubber band, a light ball made of plastic material or of pressed paper. Fix the ends of a rubber band to the two top edges of the stick. For applications to energy studies, prepare a few slings with rubber bands of different elasticity.
How to play:   hold the handle of the sling with one hand, with the other hand stretch the center of the rubber band while pinching the ball; choose the right orientation before releasing the ball.
Physics:  
  • force and interaction: the force is characteristic of the interaction between the hand and the sling and we identify it by its “effects” (stretch),
  • the force can be measured by comparing the deformation with that of known forces (calibration),
  • the force has a direction,
  • while we apply a force to the sling, the sling applies in turn a force to our hand (action and reaction),
  • the distance of the throw does not depend only on the force but on the force times the extent of the stretch, that is on the energy which is transferred from the hand to the rubber band and from the rubber band to the ball,
  • energy has different forms.
Educational aspects:  
  • discover force and interaction and different types of forces (Fa),
  • analyse the relation between force and length of the stretch (Fb),
  • discover direction of forces (Fc),
  • discover action and reaction (Fd),
  • analyse the relation between force, stretch and distance of the throw to understand the difference between force and energy (best done with bands of different elasticity - Ea),
  • discover the properties of energy : energy can have different forms (Eb) and can be transferred (Ec),
  • measure length and distance (Sa),
  • compare with your expectations.
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Last modified: Thu Nov 16 10:06:35 CET 2000