HCR - Friction Cone

==A way to visualize friction==

The friction cone depends on the $F_D$ (Force Down-ward) and $\mu$ the friction coefficient.

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• Friction Cone:
  
  
  • Where:$\begin{array}{l}\Theta =\\ \eta :\text{friction coefficent}\end{array}$(The friction coefficent ($\eta$) is specific for each pair of object interaction)
  • A force that want to break the friction is applied as shown:
    
    
    • $F_1$ is too small to break friction (the object doesn’t move).
    • $F_2$ is big enough (the object begins to move).
    • Graphically $F_1$ is inside the friction cone.
      While $F_2$ is outside the friction cone
  • Knowing where the friction cone is, and how big it is, is extremely crucial, because if i want to apply force to the object without it slipping out (break friction) i need to apply all the forces such that they stay inside the friction cones.

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• ~Ex.: Position of the friction cones
  • Suppose we have this object:
    
  • Let’s see how the position of the friction cones is useful.
    I apply to the previous object 3 forces: $F_1,F_2,F_3$, resulting in this 3 friction cones:
    
  • Take now an opposite force $F$ that tries to break friction.
    It is clear that where i apply the previous 3 forces changes the intensity of the Force $F$ needed to break friction: