Explicit physics instruction
Center of gravity determines where the body’s weight can be modeled as acting for torque analysis.
Stability increases when the line of action of weight remains within the support base.
A low center of gravity and wide support base generally improve resistance to tipping.
Core relation: τ=rF⊥ and Στ=0 in rotational equilibrium.
Worked example
If a 10 N weight acts 0.20 m from a pivot, an opposing 5 N force must act 0.40 m away for equal 2 N·m torques.
Guided question
Why can widening a support base make tipping less likely?
Independent work
- Solve three torque or balance cases.
- Draw a pivot/lever-arm diagram.
- State one assumption or uncertainty.
Misconception check
A larger force does not always produce larger torque; lever arm and force direction matter.
Formative check
What two geometric features determine torque besides force magnitude?
Reveal response
Distance from the pivot and the force’s perpendicular component/direction.
Mentor evidence conference
Ask Archaemenes to audit pivot choice, torque signs, lever arms, and equilibrium assumptions.
Teacher guidance
Foundation: Calculate perpendicular torque.
Core: Solve multi-torque equilibrium.
Extended: Analyze stability and uncertainty in a lever model.