1K10.20 Slipping Ladder (Ladder Against a Wall)


Torque, friction


A ladder leans against a wall, on the verge of slipping. A hooked mass can be moved up the rungs of the ladder until the ladder slips.



  • [1] Model ladder
  • [1] Wall
  • [1] Wooden plank
  • [4] C-clamp
  • [1] 1 kg mass
  • [1] S-hook
  • [1] Metre stick

Classroom Assembly

  1. Clamp the wall to a table.
  2. Clamp the plank next to it.
  3. Lean the ladder against the wall.
  4. Place the metre stick next to the plank and the ladder for scale.


  1. Find the angle at which the ladder starts to slip.
  2. Hang the mass at various rungs of the ladder, going up from the lowest rung.
  3. When the mass reaches or passes the middle of the ladder, it should slip.


Additional Resources


  • PIRA 1K10.20
  • The University of Kentucky's Department of Physics and Astronomy has a decent video performing the demo.


  • Don't attempt this at home!

Last revised

  • 2019


Related AV

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.