Forces and equilibrium

What the syllabus asks of you

• identify the forces acting in a given situation
• understand the vector nature of force, and find and use components and resultants
• use the principle that, when a particle is in equilibrium, the vector sum of the forces acting is zero, or equivalently, that the sum of the components in any direction is zero
• understand that a contact force between two surfaces can be represented by two components, the normal component and the frictional component
• use the model of a ‘smooth’ contact, and understand the limitations of this model
• understand the concepts of limiting friction and limiting equilibrium, recall the definition of coefficient of friction, and use the relationship F = μR or F ≤ μR, as appropriate
• use Newton’s third law.