Equilibrium
Forces and Motion

Slinky Drop

Enrichment Activity for 5-11 11-14


What you need

  • A slinky
  • A friend

Instructions

  1. Hold the slinky up at arm’s length by its top coils
  2. With your friend keeping a close eye on the bottom of the slinky, let go of the top (you may need to do this several times to see what’s happening)

Results and Explanation

The bottom coil of the slinky remains stationary until the top coils reach it and then the whole slinky drops to the floor together!

When the top coils are released, the forces on the bottom coil (the tension in the spring and gravity) are still balanced. It is not until the slinky has contracted that gravity exceeds tension in the bottom coil and it starts to fall.

Equilibrium
can be analysed using Force
has the special case Thermal Equilibrium
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