BRAINCAKEForces in Equilibrium
Revision notes for Forces in Equilibrium in AQA Physics (7407). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Vector and Scalar QuantitiesPhysics is about physical quantities.
- Vector QuantitiesA vector quantity has both magnitude and direction.
- Adding Vectors - Scale DiagramVectors can be added by using a scale diagram.
- Resolving VectorsAll vectors can be split into two components perpendicular to each other.
- Adding Two Perpendicular VectorsParallel and anti-parallel vectors are simply added together as they are in one dimension.
- EquilibriumAn object is in equilibrium when all the forces acting on it are balanced.
- Three Forces in EquilibriumAt equilibrium: Note: the horizontal components are equal.
- MomentsAn object in equilibrium has no net force acting on it and no net moment (rotational equilibrium).
- The Principle of MomentsThe principle of moments states that for a body in (rotational) equilibrium, the sum of clockwise moments about any point is equal to the sum of…
- Centre of MassAn object's gravitational force (its weight) acts through a point called its centre of gravity.
- CouplesA couple is a pair of equal and opposite forces acting on a body along parallel lines.
- Stable EquilibriumStable Equilibrium When an object is displaced, it returns to its equilibrium position when released.
- Tilting and TopplingUnstable Equilibrium If an object is tilted, the object will topple if the displaced centre of mass is no longer above or below the point of support…
- TiltingAn object at rest on a surface is acted on by a force that turns it clockwise or anticlockwise about a point.
- TopplingA tilted object will topple if the line of action of its weight passes beyond the pivot A uniform block will topple if the tan of its angle of tilt…
- Objects On a SlopeFor an object on a slope inclined at θ to the horizontal, it helps to resolve its weight W into two components: Wsinθ acting down the slope and…
- Free Body Force DiagramsA free-body force diagram isolates all the forces acting on an object.
- Triangle of ForcesAt equilibrium there is no resultant force and no resultant moment.
- Condition for EquilibriumAn object acted on by several forces is in equilibrium only if two conditions for equilibrium are both met.
- How to Lift a WeightLet W be the weight of the upper part of the body, T be the tension in the back muscles, W0 is the weight to be lifted and R is the reaction force…
On the specification
- 3.4.1.1 Scalars and vectors
- 3.4.1.2 Moments